We've already talked about ways to get your RSVP's answered...now let's talk about those guests that don't bother to return the RSVP, don't answer any messages you've left, and still show up at the event! Or those that show up with extra guests that were not invited... Or those that show up with kids for an 'Adults Only' event...
First of all, we always place the most responsible and polite hostesses on the front entrance handling the seating chart and placecards. These hostesses will handle your guests and any issues politely, courteously, but firmly.
We also recommend setting up one extra table for those 'special no-RSVP' guests. Fortunately, most caterers do prepare at least a couple or so extra plates. If you have "one of those families" or a bunch of friends that you know are not the RSVP type, add in a few extra plates to your final count. Otherwise, if there is seating outside of your event room, the guests should be asked to sit in a separate area of the venue until after dinner is served and then be allowed to join the party after dinner. Or give the guests the option of waiting in the designated area to see if there are no-shows who RSVP'd after the majority of the guests get there--the waiting guests can fill-in those seats. Also, the good thing in this situation is that there are always some guests that do RSVP and don't show up or call at the last minute to cancel (after the final count has been given) so you can fill in with those guests first.
You have two choices: if you have the budget for it, pay for the no-shows (only if you have no last-minute cancellations). If not, ask the guests to pay your per person fee since they said they weren't coming originally. They will either pay or go home...sorry! To be clear, we think it is tactless to ask them to pay...but that is your decision (after all, it was tactless for them to not RSVP). But, a budget is a budget!
As for children showing up at an all-adults event, there should be no exceptions. Most hosts now set up separate areas or rooms for children for out-of-town guests with an event sitter service. You would have already advertised this on your website or in your invitations, so kindly ask the non-compliant guests to take their children there providing they pay the sitter fee (if the service was already prepaid for by you). Otherwise, they will have to go home...again, sorry! Letting them stay would be totally unfair to the guests that adhered to your requests of no kids.
This article was a must-do article because if you do events you will have to deal with this sooner or later. The point is, there is no easy way to deal with non-RSVP show-ups...but hopefully we've helped to give you the best options.
Moral of this story...if you are on the other side of the invitation as a guest, respond as soon as possible to the RSVP deadline and follow the event requests. It's just plain 'ole respectful and courteous!