I've sold coins there, and people do every day. But the point of your question is not what happened in the past, but what *might* happen in the future. And that unfortunately no one really nows.
They've taken steps to ensure full registration with any applicable laws and regulations. But a bank can close an account for any reason, valid or not.
Agreed. It is impossible to predict the future. We can only hope that Coinbase has taken all precautions and steps to make sure the banking industry stays happy.