Inappropriate or no?

A co-worker of mine is getting married next summer. Her and her fiance are in their early twenties and are on a strict budget. Because of financial constraints they decided not to have +1's at the reception so when the invitations went out there were no spaces to write in a guest.

Yesterday she tells me that one of our other co-workers RSVP'd and wrote in the name of her boyfriend as her guest. Naturally she is really irritated and doesn't know whether or not to say something. So my question is: Is it tacky to write in a +1 if the invitation doesn't explicitly state to do? Should my co-worker let it slide to keep the peace or be honest and say something?

What do you guys think? I think it is inappropriate because the invitation already tells the guest how many people they can bring, unless your coworker worded the invitation poorly. Do you feel like it was very clear that they didn't want the +1's?


Generally, if you don't want to leave the number of people open your invite will say something like "X# of seats have been reserved in your honor" and/or it will be addressed to "Miss Co Worker" or "Miss Co Worker and Guest". If it's not going to cause a huge problem she should leave it alone. If that one extra person is the difference between the up-to-75-guests package and the 76-150-guests package, then she should say something.