Why would you camp anyway?
I see that it's the jb_snow map in the screenshot. It's a big map, which is why there is no reason to camp at all.
M249, regroup, cover while others reload - zombies will attack, but the fight will be even.
Heck, even in small maps like xmf you shouldn't camp. You shouldn't tolerate players delaying the end of the round by that course of action.
Fast - paced rounds is the only way to keep the player base going.
If I was in the server when something like this would happen - I would use 1.warn 2.slap tactic without hesitation.