i dunno if i agree...
personally i see way more familiar faces in cash games, and fewer in MTTs.
Maybe in SnGs i see familiar faces, but the odds
of that are far less than seeing someone who plays say NLHE $1/2 10 handed, and i see them like every three sessions.
I definitely think it's worth a bet to get some info on a ring game regular that I could use to get a whole pot (or more) from later on.
You do bring up a good point though, spore. I generally will only do this (pay him off for info) if he's playin in a way i've never seen before. Obviously if he's doing something i've observed before, i'm not going to pay him off.