ill keep this short... when big faction group enters for example into NCR they're able to steal plenty of loot from some place of the map by killing all guards (or hostile to them Npcs)
for example, there should be a storage building full of ready-to loot stuff like CAWS, P90C, and ammo. (maybe chance to get ranger armor) with electric gate as the only way in... when all guard npcs die, there will be message "NCR has been raided"(same time storage gate opens) same way as TC message(reinforcement NCR soldiers dont affect guard count, but theyll keep coming to kill you). and then you have chance to loot everything that storage has and run for your life because NCR soldiers will keep and keep coming at you till you leave the city. (for example 10-15 NCR soldiers and/or rangers coming every 1-2 minutes, all in CA because they protecting own city)
i think its balanced.... NCR is hard to raid with one big gang i bet, especially with reinforcement thing implented.
pros: good prizes + alliance of other gangs is allowed
cons: every bluesuit with a gun is able to shoot you down and loot you if he got a chance + NCR soldiers coming as a backup + 10 real time hours timeout to raid that town again.
when last character leaves storage room, its gate closes.. then goes 1 minute and all ncr guards respawn (the ones originally protecting NCR) (and anyone exploiting that, AKA going into the room in time, he will be teleported outside storage after 3 seconds of gates closing)
imho that can make it a huge battleground whenever gang feels doing that...
and if youd be a solo, never even try getting prize then
sticking together is a power
UPDATE: those 10-15 ncr soldiers are them who patrol near ncr, if faction that raids the ncr isnt finishing raid in time (15-20 minutes) there will spawn 40 ncr soldiers with best equipment to destroy you (...because so many think that its too easy to raid)