Maybe. You can just walk into a bank and claim you are robbing them, and walk out with money, because tellers are trained not to refuse. Is that a security loop

Maybe. You can just walk into a bank and claim you are robbing them, and walk out with money, because tellers are trained not to refuse. Is that a security loophole? Probably not, because you can easily be tracked and caught. Similar with the stock market. If you find a "bug" it's likely that the SEC will want to have a chat with you.