I don't think that there is danger in bitcoin, what we should really fear is the users or the scammers so we need to do more research before joining any investing or trading transactions.
Scammers user usually bring our money leaving only promise good profit which we will get in future. For example scamming through exchanger have this some characteristics such as offering the lower exchange rate, promise anonymity or offering easier withdrawal but actually they not really that easy feature. All of that only fakes. So we must keep be careful with bitcoin, on the wrong hand bitcoin can become dangerous.