Its probably more annoying then helpful but definitely not cheating as it is available to everyone. Everybody is free to put a dot on their screen if they think it's help. Otherwise it could be considered cheating e.g. using a TV with a low input lag. I think it's a pointless discussion anyway as there will be nobody to control the screens, controllers, etc. of the players. I don't give a damn if players decorate there whole screen with diodes and colors, buy controllers with extra buttons, etc. They will get shot anyway.