It's a hard lesson for many, and it'll likely need to be learned many times over. Any number of individuals are willing to take advantage of the trustworthy nature the technology to imply that the things they do are also trustworthy.

And too often, it works - because the technology is secure, not enough people question those who are using it and proclaiming "secure" in a loud enough voice (mt gox, cryptsy, mintpal, and countless others).

It's also a first-class lesson to a lot of young technologists as to how financial regulations and the modern banking system came to exist in the first place. Thankfully bitcoin was so well designed that we can ultimately trust the math behind it, but the code is still malleable by people who may not have the network's best intentions in mind.