Buckingham Palace confirmed that Prince Harry will be in attendance for King Charles III’s coronation on May 6, while Meghan Markle will remain at the couple’s California home with their two children, Prince Archie and Princess Lilibet.
News of the Duke of Sussex’s confirmation – on Wednesday, April 12 – comes days after the palace’s RSVP April 3 cutoff date passed, which left royal watchers wondering if the prince would attend his father’s ceremonial ascension as king at London's Westminster Abbey.
Fox News Digital reached out to representatives of Buckingham Palace and the Sussexes for comment.
While the reason for Harry’s seemingly late reply is currently unknown to the public, etiquette experts, event planners and psychiatrists are advising everyday people to respect RSVP deadlines for special events.
Here are eight questions event hosts and guests should consider before sending out formal invitations and reply cards.
Laura Windsor, a British etiquette trainer and founder of the Laura Windsor Etiquette Academy in London, told Fox News Digital that recommended timeframes for sending event invitations ultimately depends on the formality of the planned occasion.
Invitations to casual suppers, dinner parties and similar small gatherings can be sent out a couple of weeks before the event date via mail, phone or email, according to Windsor.
"Invitations for formal events should be sent out no more than six weeks before the event and no less than four weeks in advance," she said. "If invited to a big event such as a wedding, an invitation should be sent out at least 10 to 12 weeks prior with a reply card enclosed."
Windsor noted that some hosts opt to send save-the-date cards in advance of a formal invite, which she thinks is a "rather American practice," but it’s also an "acceptable" practice for today’s age, especially if a host wants to secure attendance from guests who live far distances from where the event will be held.
"Written invitations still remain the most elegant way to announce social occasions," Windsor said. "It not only sets the tone but prevents confusion about dates, timings, location, dress and the kind of hospitality provided."
Windsor advises hosts to include a deadline to reply on invitations, so confusion and misunderstandings can be minimized for guests "who are not aware of RSVP etiquette rules."
Ideally, guests who receive invites to an event should RSVP as soon as they've figured out that they'll be able to attend.
Windsor told Fox News Digital she recommends invite recipients to respond "no later than 48 hours" of when they receive their invite.
"Sending a reply right away prevents you from forgetting," she explained.
Windsor noted that guests should also make sure they promptly submit their RSVP in the fashion that’s listed on the invitation.
"If an address has been listed on the invitation, then it is correct form to reply by handwritten letter," she said. "Should the RSVP list a telephone number, then it is acceptable to call."
Danielle Rothweiler, owner and lead event planner at Rothweiler Event Design in New York City, told Fox News Digital that last-minute and late RSVPs are a "constant issue" that hosts deal with when planning a wedding or a special event.
While most guests don’t intend to make event planning more difficult than it already is, indecision on attendance "can create huge issues" the longer it takes to submit an RSVP, according to Rothweiler.
"The caterer and venue need a headcount to prepare the amount of food they will need," Rothweiler explained. "A seating chart and floor plan will have to be adjusted which can cause a ripple effect."
She continued, "These are not issues anyone throwing a party needs to deal with at the last minute."
Rothweiler noted that taking a few days to decide if one wishes to attend an event is fine, but she urges guests to send RSVPs right away.
While most event hosts are likely to understand that life happens and there are various circumstances that can lead to hesitance or a late RSVP, but event planners and socialization experts say some reasons are more acceptable than others.
"If you are invited without a plus one and that is your reason for not attending, then telling that to the host will only cause an argument," Rothweiler told Fox News Digital.
"It's simple enough to say you have a prior obligation and leave it alone," she went on. "You do not need to give a reason for not attending and it would be inappropriate of the host to ask."
Carole Lieberman, a Beverly Hills-based forensic psychiatrist with OnlinePsychiatrists.com, which has psychiatric practices in New York, New Jersey and Florida, told Fox News Digital she thinks guests can relay what’s holding up their RSVP decision to hosts if they feel comfortable doing so.
"Whether a guest’s delay in RSVPing is acceptable depends upon how much their presence or absence would disrupt the host’s plans and how serious the excuse is," Lieberman said. "In any case, the guest must be honest with the host as a courtesy, and sometimes the host can offer a solution to the problem."
Issues that hosts can help find solutions to include travel arrangement assistance, finding a reliable babysitter or suggesting budget-friendly options, according to Lieberman.
"If scheduling or health may be a problem, depending upon how other commitments work out, or how quickly someone recovers, then give the host an idea of when you would know," Lieberman advised.
Lieberman doesn’t recommend guests hold out for other event invitations because doing so could backfire and make the invite recipient look worse if they’ve left their RSVP unanswered.
"Under no circumstances should a guest lie, because if they are waiting for some better invitation to come, the host may well discover this when a mutual friend happens to mention that they saw you at so-and-so’s party," she warned.
Guests who figure out that they can attend an event after the RSVP deadline shouldn’t assume that their attendance is still welcome, according to Lieberman.
"If a guest's RSVP would come after the deadline, it is only polite to apologize and check with the host beforehand to see if they are still welcome or if it presents a problem," she said.
"A late RSVP would likely change the seating arrangements, catering, activity plans and so on," Lieberman noted.
In cases where invites are rescinded or can’t be accommodated because an RSVP hadn’t been received in time, aspiring attendees are entitled to their feelings, but they must respect the host’s prepared arrangements, according to Lieberman.
"A guest may well feel disappointed or angry if their host tells them that their RSVP can’t be accommodated," Lieberman told Fox News Digital.
"If there’s a good reason, the guest will just have to accept it as a life lesson and RSVP sooner in the future," she said.
Lieberman believes invited guests who are related to or have a close relationship with an event host should know that they’re reasonably expected to provide a swifter RSVP.
"Family members and close friends are expected to reply sooner, but sometimes these are the very people who expect the host to give them special treatment and include them – even at the last minute," Lieberman said.
From weddings, galas, birthday parties and backyard barbecues, Lieberman advises invited guests to send RSVPs as soon as they know they can attend, regardless of the formality of the event.
Lieberman also noted that RSVPs for children’s parties should be handled with special care.
"The birthday child is often anxious that their friends won’t show up, so parents should send out the invitations early and keep track, as the party gets closer, of who is definitely still coming," she explained. "This is not only to make sure there are enough ponies and party favors, but to be able to invite more kids if the RSVP count is too low."
Lisa Mirza Grotts, an etiquette expert in San Francisco who has 23 years of experience advising corporations and private citizens, told Fox News Digital that she believes a sending prompt reply is the best course of action.
"Just as it is polite to thank people for gifts and other acts of kindness, it’s polite to acknowledge an invitation," she said. "Instead of making your host agonize over your reply, why not be the guest who amazes them by giving them the courtesy of a lightning response?"
Grotts warned that she doesn’t advise people to follow Harry’s reported example and that non-royal guests who are invited to special events can put their invites at risk of recision if a response is delayed too long.
"It’s impossible to think that Prince Harry has been straddling the fence to attend his father’s coronation," Grotts said. "We will never know what happens behind closed palace doors, but one thing is certain, the cutoff date had come and gone."