we had a few 'sorry i couldnt make it, im ill,' and those ones were the suspious ones who RSVPed at last minute because I chased them up. clearly having no intention of coming as no card appeared in the post (which you would have assumed they would have bought if they were going to come)
but worst was a very close friend, who didnt respond to invite at all, and didnt bother to show up either and heard nothing from her - that hurt a lot.
on a positive - we also had one amazing guest who was other side of country the day before for her grandmas funeral and traveled for over 6 hours just to come to evening reception! just shows who your true friends are