I'm not sure it's changed. There have always been a lot of flakes.

I used to ask for deposits on a case-by-case basis, but recently implemented a strict policy of deposits for all new friends. I don't ask for deposits after the first session although I do warn subs that I will require a deposit for every session if they become flakey.

I do find clients are a bit more open to deposits than they used to be but that might just be because I've been around for a decade now.