I've certainly noticed the change in that almost all Dommes in the last year or so now require deposits, to deal with a real problem of time waters and no shows.

I think kink.com bears some blame here too, although they may just be an early casualty of the blurring of BDSM and the straight sex scene. It's a bit of chicken and egg, so I'm not sure which came first. But they've been so influential in exposing new people to BDSM it has to have had some effect.