Dear Emily,
I dont personally see the stigma, but many do. In fact, society as a whole attaches a real stigma to it, and says the behaviour is so unacceptable that, if you're caught, society through its LE mechanism will impose criminal sanctions on both guys and gals. PMBs make mongering seem OK, and from the posts, such as, "are you LE" etc, only show how uninformed many are about the risks associated with this. I'd go so far as to say that only a small percentage of guys actually act to mitigate their risks in this area.
Actually, I think the guys who 'hobby' are all fairly mainstream. Its actually more interesting to watch the ads on CL or BP to see how chicks are selling and at what price point and then extrapolate to how the economy is doing, because this 'hobby' is mostly about totally discretionary funds being spent.
Because there are many more users on UG than active posters, I find it difficult to label the active posters as 'average'. Just as its equally difficult to label a provider who actively posts here as average or representative of the commercial sexual services industry.
your pal, being serious this time,
h4c