Main stream adoption will only happen if those that want it can have the security blanket of fraud coverage to cuddle in. The answer here is still a non-regulatory, market solution: Crypto Insurance. Non-transparent, un-auditable coins and exchanges simply won't be able to be insured. People can decide if they want to speculate using uninsured currencies and exchanges. My prediction is that non-transparent, sketchy schemes will wither. Of course, the insurers themselves need to be sound -- but Lloyd's seems to have solved that problem about as well as it can be back in the days of wooden ships. This is not a new concept.