We've started contacting people about RSVPs, and I've gotten some pretty lame excuses so far. I'm not going to complain because our count is high enough at this point.
Here are mine so far:
"Sorry I can't make it. I have too much to do around here."
"We're going to be working in the field that day."
"Sorry we can't make it. That is my weekend to work."
Save the Dates were sent to these people...they've known for 7 months.