Not the U.S. thing, but a new idea being trialled in Serie B this season.
The idea seems to be to reward positive behaviour like kicking the ball out if an opponent injured and even admitting to diving. No card is actually issued and what’s not clear, to me, is the incentive to do these virtuous things. They’ve used it in youth football and are now looking to try it out in Serie B and then if it works in Serie A as well.