I have an aunt and an uncle who failed to respond to my RSVP. I tried e-mailing, calling (left a couple of messages), Facebook (even though I don't think they use it much), even asking their daughter (my cousin) to ask them to call me so I can get guest count information. Nothing.
Finally, after a few weeks of this, I asked my dad to give them a call. They answered that time, and said they weren't sure if they would be able to attend yet.
So although that was a bit frustrating, I accepted it since my venue does allow a little flexibility with the guest count up until a few days before.
But here is is a week and a half before the wedding, and they still haven't gotten back to me. I'm going to call (again) today, but I honestly have my doubts about whether they will answer the phone -- I really feel like they're avoiding me for some weird reason. I heard from other relatives that this aunt and uncle NEVER RSVP for anything, even when people call and ask.
So what's a good message? I was thinking of something like this: "Hi, this is ___________. Just checking in to see if you can attend the big day next Saturday. Please give me a call at _____________ to let me know. We'd love to see you there! If I don't hear from you by Sunday, I'll assume you aren't able to make it." I feel a little rude about the last part, but I also don't want them to not respond, then show up at the wedding.