Outstanding RSVPs

My RSVP date is tomorrow and we're missing a lot of cards, most of which are from FILs people. And within that group, many are from people FMIL works with. FMIL keeps telling me that her work people are giving her the run around when she asks about their RSVP (I find humor in that!) They just will not give her a direct yes or no.

So...I'm thinking that if someone can't give me a firm answer I should just count them as a 'no,' right?

I'm not talking about counting them as a no right away, but if I can't get an answer in another week, week and a half.

Your thoughts?

I would give it another day or two. Only because I am sure there are people who would wait till the last day to mail the RSVP, thinking that just because it says 'by July 6, 2006' doesn't mean it hasto be there by then just post marked by then, kind of like tax season, theres hundreds who wait till the last moment.
Forgot to add... After Friday I would consider them a no. Just beware of them showing up anyway thinking they responded in time.