I am a Dedicated COD player on 4 and MW2. Public games, Gamebattles, Tournaments.
Camping will always exist. They do it in all gaming types. Like it or not it is THERE strategy. Just how some players approach the game.
If they are behind on Kills, they Camp.
If they are going for a Big Killstreak and lack skill, they will camp.
If they do whatever and that's how they play the game, They Camp.
Adapt and Overcome. You can get pissed ( I do) but just get even. A Semtex to the face says a Thousand words.