Like most stuff in that category, they sell from non-US territories and avoid some laws usually. Bank what they can (say promise you free ppv, etc for only $100) then if they're lucky get 1000 sales or something before taking down their site, accounts, etc and moving somewhere else.
I think a lot of it is a "what are you gonna do?" clause, I mean they're sorta covered if they do it "right" and they assume since you were intentionally trying to do this too you probably won't tattle on yourself to blame them.
This is OT anyway so I'll share a story. I got this awesome (not) call when I was unemployed years back from Cut-Co knife sales wanting to give me a free training seminar to sell their stuff. Anyway turned into more of a fishing game so I passed (it's a call 100 people and ask them for names to try, etc, etc when I specifically asked upfront that these are people that called THEM not visa verse).
So they're a good (overpriced) product nothing wrong. They told us about the Ginsu scam which was actually pretty funny/smart. Everyone remembers that knife and the commercials with it cutting through everything and they sell it with a life time guarantee free replacement for life bla bla. So they sold a bunch (millions) and filed for bankruptcy. This invalidated the life time guarantee and they got their money. Later they did it one more time with the Ginsu2 which they cut through their first knife. Same sales pitch, same "oops, we're folding".
It's kinda crazy what legal scams are put out there.