Camping on map is not a real problem, camping on worldmap is.
Well there is no serious problem with WM camping, as reinforcement are very likely to enter the map when squad taking TC gets attacked (else they would stay on WM totally without sense).There is a problem with drug users and normal chars, as to take city you have to stay there for 25 minutes, which is longer than jet works.. so you risk getting caught on withdrawal.. yet you can't use normal chars because attackers can wipe you out easily with drug using chars. The solution is probably to create and use chars which would be something between normal chars and full drug users, I mean those who can be effective using 1 dose of every drug at all times. Still they won't be as effective as full drug users, so you have to get advantage from larger numbers of people in your team or using mercsAlso we haven't tested yet how using mercs will affect new TC and I've got a feeling that using the most expensive ones will affect it greatly.
Defending is always harder than attacking, because of lack of informations, drugs cooldowns, ... . So my little suggestion: Defending team (during capturing) should have info about number of players entering the city. So they will get random radio frequency and they will recieve info about numbers of players and entering location. I.e.: 3 pl + 2 npc Redding Mine.