Cofr, civilian?
One example of good conceding is, in fact, Cofr. Mostly regulars often do f4, clearly showing the victory of the other team without the painless waiting around. True, there could be cases when people f4 prematurely, but considering the high number of regulars and the 4 player difference needed to concede, it's unlikely it will be abused.
As far as spawn camping goes, it's only spawn camping when the marines can clearly walk in/siege and win and choose not to. Two marines early in game with no upgrades are keeping aliens in base, not camping. A group of marines with full upgrades against aliens with one hive mining it is spawncamping.
Aliens are different. Unless you have several aliens in the marine base, spawn camping is needed. Killing an updating armory or an arms lab would do more damage than killing an ip with one guy dead. If there are several onos sitting around the ip waiting for the next guy to devour him, then yes, it's spawncamping.
It should certainly be on the case to case basis along with premature f4ing.