[JackMonroe]

I don't ban for wallhacks unless it's really obvious.  A lot of people are in clans too so they are probably in vent or teamspeak together telling each other where people are.  I really only get suspicious when they shoot people through stuff with no previous knowledge of the person being there. 

As for the other hacks

Aimbot-  In first person spectator you could see a few different things for aimbot.  You could see when they are firing, their aimer goes all crazy and and shakey and kills lots of people with hs.  Another one is a lock on type which instantly locks on to someones head pretty much at the same exact time they start firing and will usually alternate between enemies if they click multiple times.  Third more obvious is the spinbot, in spectator the screen will usually be upsidedown and will look much like the first type when they fire.  Also, for the last one if you are looking at them in third person, they typically are staring at the ground and quickly spinning in different directions.

No recoil-  No recoil typically looks like the crosshair drops rapidly and then returns to the original position after every shot.  You have to remember when watching that legit people will pull down on their mouse when firing in bursts.  So make sure that the crosshair is popping downward after every shot rather than pulling down smoothly during a burst.

Speed-  Well, they run really fast.  Lot of laggy people on the servers so don't be mistaken about that.