The question is simple, are you going to do something against the players cheating in game?
As it seem to be already a problem
The answer is simple VAC.
If you suspect someone of cheating turn on fraps, go into spectate, and it is very easy to get good footage.
As for the people using the heavy pweapon glitch, it such a small advantage it dosnt bother me much, how ever that invisiblity glitch that comes with it is a much bigger issue, which will most likely be solved soon. (I hope)