What's the correct etiquette when you're planning a party and you have an RSVP date on your invitations and people haven't responded yet. Do you gently remind them prior to the RSVP date not to forget to RSVP? Do you wait until the RSVP date has passed and then see if they are coming or not? Or do you just assume any non-responses are a not-coming?

My mom is planning my baby shower and she's hosting it at an event center where she needs to give them an official head count since they are serving lunch. She sent out the invitations over a week ago with an RSVP date of January 11th (this Friday). She has to tell the event center by January 14th (the following Monday) the total head count. Some of my friends haven't RSVP'd yet - I'm curious if I should do anything, wait and then do something, or don't do anything?