If you choose to _sell_ at $1 you will likely get a warning because it will fill instantly at the current market rate despite being a limit order. However you can choose to buy at $1 and there's no reason for it not to be accepted into the order book. In fact you often see this via Nasdaq TotalView during low liquitiy events such as right as the premarket opens where someone is bidding $1 or $0.01 for shares of a blue chip company.

The same applies in reverse.

I don't know about refuse, but if it did go through it would definitely raise a bunch of red flags from the anti-money laundering checks, IME these are taken very seriously. Accounts involved would probably get locked pretty quickly.

I think that's the broker that does that