Poloniex is registered with USA FINCen nationally as an MSB in the state of Montana.
If they stay in compliance, and don't get in hot water with the SEC, they should be OK unless the legal landscape changes.
True. But I think the "ICO" is very clearly in violation of the law. This creates a liability when they are sued by investors who lose money as a result.
Which law specifically do you think is violated?
Lawsuits are civil matters, one could be sued for anything at any time. This liability exists with all business and is a different matter entirely than lawbreaking.
Some problems that they don't have:
The primary defense for poloniex is as the service provider, they are not an adviser or broker, they provide no financial advice.
For currency exchanges in particular in the State of Montana no Money Transfer license is required. Not even USForex has one in the state:
http://www.usforex.com/about-us/legal#MTThey seem in compliance, but I have no special information regarding their operations so don't take my word for anything, ask them if you have a concern.
If they start offering Securityies with the BitsharesX stuff, they may need to register under Section 6 of the SEC Exchange act of 1934.