I'm totally with you on this. We stopped helping people move a while ago for much the same reasons. For my last two moves I hired professionals to do it. It cost a lot more but saved the hassle of a)annoying friends and it was b)over quicker c)less hassle for me.

Since my work-related injury to my hand/wrist years ago, I can't lift stuff anyway so I use a small luggage trolley to shift stuff that others might be able to lift. We have 2 - 3 of these and they are really really useful. Can even be used to move bookcases!