I don't really care if you're using a glitch to get to a top part of a map so you can sit and snipe because after you kill me the first time 1.) I'm going to know where you are by watching the kill cam AND 2.) I'm just gonna sit and wait for you to pop out again and cap you in the face.
BUT
My problem is when people use a glitch to get "inside" the walls, or into other parts of the map. Hydro Dam is a great example; I know a couple guys that I play against often that just sit inside the wall the entire match sniping. It's pretty weak because they can shoot out from the wall, but people can't shoot in... so it's just 10 minutes of kill streaking snipers picking everyone off constantly.
It's just like - WTF? Give it a break once in awhile.