You must be new to online gaming.
Camping has been a Cheap tactic since Doom deathmatches way back in 1993.
I find it funny when I die to a camper and it shows his killcam and all he is doing is sitting there with his red dot on an opening just sitting... waiting... and waiting... and waiting... then kill... woohoo so much fun...
The only thing that really bugs me about campers is how lazy it is. If everybody camped........no one would ever get any kills.
People play how they will but it will always irk me how lazy camping is. I'm not talking about defending anything either, I'm talking about good old fashioned sitting in a corner waiting for some porr unsuspecting soul to run by.
Lazy. Other than that, once you learn the maps they are fairly easy prey.