I'm going to go through and rewrite some of the suggestions, I think, although my basic idea still remains, it is possible to apply similar tactics, training (if you have it) and concepts to paintball.
I actually had the pleasure of playing against my area's sniper/marksman this summer when playing a 3 vs. 3 attack/defend game, he double tapped me when I was caught up suppressing someone else, his first shot missed, but his second shot hit my knee (I was crouching, so my knee was only slightly below my centre of mass). I never saw it coming.
Sequence of events:
1. I advance to the far right flank, I have a river at my back, a fallen tree for cover and a clear field of fire into dead ground which the enemy must advance down sooner or later, although my view is slightly obstructed so I cannot see my captain, or the far end of the dead ground.
2. Our captain takes the middle, which has some cover and a view into the same dead ground as the one I watch, but can see further into it.
3. The newb also goes to the middle, and watches the same direction as the captain, instead of guarding our left flank, which our captain tells him to do, as he hears a noise, even I heard the command, but the newb ignores him.
5. Enemy appears on the far end of the dead ground, but I cannot see him, he and the captain begin to trade shots, I remain in place though, as I have no clue where he is and little cover ahead of me.
6. The enemy on our left flank who was lying in wait opens fire, he immediately take out the newb and opens fire on the captain.
7. The captain turns to face the threat, and I, to relieve him, advance forward and inward and begin suppression firing on the guy at the far end of the dead zone, even though he is too well covered to hit.
8. I get double tapped by the sniper, who was waiting in undergrowth on a ridge to the middle left side of the dead zone.
9. The flanker takes out the captain.