Indeed jcheese. Forget the arguments about whether it's fair or not. If you go down the line of "his bit of kit gives him an advantage and that's not fair" then the inevitable end is that everyone must have exactly the same kit "to make it fair".
The real problem with these things is that they are dangerous! You are not physically behind the weapon. You do not have the field of view to ascertain that someone isn't about to stick their bonce in front of your barrel and get a mag full of bb's behind their goggles.
Mark is usually extremely strict on blind firing, for exactly that reason. The same reason you can't stick your barrel up against the gap between door and frame, or fire through a hole you can't fit your head through.
I'm amazed these guys were allowed to carry on using those sights, if the issue was brought to the attention of the marshall team.
Da Sheriff, yes, you do sound like a bit of a prick saying that. Deliberately aiming to hurt people, or cause damage, because they haven't taken a hit? How do you know that they felt it? They might not know they've been hit. Even though we all go in to the game knowing there is the possibility of getting hurt, if I ever believed a player was deliberately setting out to injure people, then their feet wouldn't touch the ground, and if they DID manage to injure someone, especially a potentially permanently disfiguring, and definitely very expensive, broken tooth, then I'd consider reporting them to the police for assault.
And I'm afraid, when marshalling, if I hear someone shouting "take your hits" it's they who will receive the bollocking!
If you have an issue with a player, then call a marshall over to deal with it. It's their job and in most cases they're pretty good at it. Call the marshall, explain the problem, move on and enjoy your day. I've heard stories (possibly apocryphal, but believable) of people having a 20 minute firefight with a guy behind a door, calling them all the names under the sun and screaming at them to "take your f#####g hits!!!!", only to be told once he'd wasted several mags of bb's that he'd been having a firefight with his own reflection.
If you "cheat call" you just look like a twat. And as for trying to hurt someone because they don't take the hit, that's sick and dangerous, and I hope I never have to play with you if you behave like that!