Guess I misunderstood your question. Heavier BBs will hit harder and with a louder noise, and also be more of an indicator of 'being sniped' than any paint filled ball which would be really bad for consistancy. And still, it's up to the player to tell if they got hit or not. Paint mark or loud smacking impact, people will ignore it as they choose to. That's where the scope and the second and third kill from the day comes in. Up to you to put a round on target, if it takes you three shots with impacts on a guy and he finally calls hit, that's three kills for you, you just loudly bring it up later in public that they didn't call hit, and thank thhem for your mulitple kills. ;)

yup exactly, in paintball when people wanna cheat and ignore a hit when they are hit they'll take a dive and slide through the grass a bit to wipe it off and say they ducked it.

it's better off just delivering un-ignorable pain to the person, face, stomach, biceps, and calf's are the best place to hit someone who's being "invincible".