Players often fight in the sewers to hunt for the stamps, gather Tel Var and key fragments, clear the mini-boss zones, battle the flag-carrying bosses, and make their way to the center for Molag Bal's event. And, of course, to fight other players.
It was the referrence I found to the sewers so I got curious if this was a grinding teq. for CP xp or what as I never really been in the PvP zone much. :-) But thanks for the answer, that's something I can look more into:)