See here for the trial rule. I have played with this rules in a junior indoor league and I didn't like it. I like warning all the players with the green, and then have them know that any foul like that they'll be off for two mins or more. Plus, since a yellow card is two mins short-handed, in indoor it seems rather stupid to have the green just be the minimum requirement for the yellow. Anyway, I haven't umpired for long and I'm just wondering what you people think. EDIT: I know the FIH rule is for outdoors only. The indoor league's organisers decided to put it in to our tech regs and they liked it.