The pin is good, but why the quarry? Maybe I'm a noob, but aren't you supposed to try your opponent's hands? You'd just give him a 1-card hand every turn. Besides, what if it's 3-player?
The quarry is to buy King's Court and Goons, which you need for the pin. Since all you need is actions, Quarry is basically cheap Gold.
It does actually give them a 0 card hand each turn, if you have no cards in your deck after you play Masquerade and you trash whatever they give you so they can't pass it back. They discarded down to 3 when you played Goons, and they pass you those 3 cards if you King's Court the Masquerade, so they have no cards left.
3-player is kind of ruled out by the problem: how do you play 3-player Rock-Paper-Scissors? Who wins if everyone throws something different? Most people play Rock-Paper-Scissors 2-player, so it's pretty much assumed.