What does RSVP actually mean when guests just tap a button?
The French still means please respond โ the tapping is the responding. On a digital invitation the reply button is the RSVP card: it names the guest, says yes or no, and drops the answer straight onto a list, where a posted card might once have sat unopened on a hall table for a week.
How late can guests reply, really?
Until the deadline you printed on the page โ after that, the plan is fixed. A late yes can often still be squeezed in, but the courteous move is a message asking, not an arrival. A late no, on the other hand, is worth nothing to anyone; that one needs no apology at all.
Is it rude to send reminders to people who have not replied?
Less rude than the alternative of a host guessing. A reminder sent privately to each unanswered name is polite mechanics; asking the same question again in front of a group chat is the genuinely rude version. The etiquette test is only this: chase the absence quietly, and thank the presence publicly.
Can I change the reply deadline after sending?
Yes. Because the page can be edited anytime, an extended deadline is visible to everyone the moment you change it โ including guests holding a link forwarded weeks earlier. Say so in a message to anyone near the answer, and the invitation stays honest.
What if a guest says yes on the page but does not turn up?
It happens on paper too; the difference is that a page knows. QR check-in at the door keeps the real count as the night starts, which settles the quiet arguments about chairs and cake after the fact, gently and with receipts.