I don't think it was scam! Yesterday I got about 3btc from PRO by buying < 400 and selling >450. And since it began to drop down, I've bought from 200 to 50 (total >1btc). So I still got over 1btc. And now people continue to buy 4btc at 80 and nobody sell at that price.
Scam with people who believe in what the quarantee??? For those thing, you can hold at 500 why don't you continue hold at 50-80? and while i'm typing, it grow to >100?