For example, Kraken appears to be a pure scam.
I put 100 BTC into Kraken when it first opened, since it was advertised as being "less safe than Starfish, but more safe than Pirate" or words to that effect.
Then I received the first bulletin, which said that almost all funds were invested in Pirate's scam.
I complained, saying that I understood Kraken wasn't going to be used for Pirate deposits and got my 100 BTC returned immediately.
I don't understand why he would return my deposit if it was intended as a scam from the outset.