What firm? There is no firm, only one guy trading for another guy. And brokers can't know who is at the keyboard. An audit would show nothing. Also, instead of bullshitting, show at least one story about anyone being charged by the SEC for trading for a friend? The only story I found is about an SEC employee trading for his mom and for a friend without any problems. He was only charged with some ethics violation for trading from work (SEC office)
BTW, Collective2 allows anyone to trade for strangers, even if you don't trade yourself, just send signals to C2 and they will execute trades in subscribing accounts belonging to people that you don't even know.
By accident, say they call the account owner for whatever reason and they let it slip that someone else is trading the account.
Futures. Each person that trades the account MUST be disclosed to the broker or FCM. These are exchange rules Tag50. If you submit your UN ad PW to anyone else, you are not in line with exchange rules.