The spawn protection system will be expanded to other classes in the future, depending on how well it works out for civs. I don't think there are any problems with it, but if you have a remark or something, please let me know.
We have to think about a couple of things first though, when expanding it to other classes. First of all, as said here, for the president. For that, I'll probably make a combination of a timer and a zone. The pres will lose his spawn protection, if he leaves the zone (the zone will disappear once he leaves) or if the timer runs out (let's say 30 seconds or a minute): then the zone would disappear as well, giving the terrorists an indication when it's safe to move in and start shooting him. But then we also need to think about what will happen with the securities who have been killed and respawning (maybe only a timer when the pres is still in the spawn zone, but a zone when he's out of the spawn zone?), because otherwise you'll have a pres surrounded by securities you won't be able to kill. Then there's also the problem that might arise from the cop spawn. If we have a zone right there as well, what if the pres goes to camp there? Maybe disable the zone and only have a timer when the pres is in the zone as well?
These are all things I still have to figure out before I can expand the system. But if you have any suggestions or remarks on how to improve the system, you can do it here.