I mean...obviously you just send the RSVP back with a "no," but does anyone else have one of those acquaintances that do the whole, "You're definitely coming, right??? You're coming???" thing? Long story short I have an acquaintance from freshman year of college that transferred away, and we kept touch online, mainly because she's never had a job and would IM me during work. We were close about four years ago, but she started dating her now FI and became obsessed with getting him to propose (like, 1000X worse than the NEY girls). Since I started school last year, I put the brakes on by blocking her on IM and keeping some distance. She still writes on my FB a LOT and emails...not really to ask how I'm doing, mind you, but to make sure I'm going to the wedding...and I kind of hem and haw around it, and usually don't respond, because how do you tell someone eight months in advance that you can't go to her wedding??? I know I'm just being a sissy, but she doesn't have a lot of friends and I feel bad. Sidenote-- the wedding is 900 miles away and in a VERY cold part of the country on new year's eve. I would go if it were close and wouldn't cost us almost $1000 to attend.
