This card is one that should be feared by all players. Cheap, and easy to invent, it sees a lot of play. Essentially it allows the forcefield wielder to buy their way out of a losing hand rank. If they buy their way to a draw? Guess what, both sides will take a casualty! Very dangerous as it permits even the lowliest chump dude to force the discard of your best guy in a 1v1 shootout, provided he has enough ghost rock to use the resolution ability. So before entering into a shootout with a forcefield guy, check the guys stash to see how many handranks he can make up. Deny him funds, and you have nothing to worry about.
This card is ideally countered by denial of funds. The other antigadget options include Faithful Hound, No Funny Stuff or simply a Shotgun to the face before the draw for the shootout even starts.