why would you swap to non-faction characters while doing the spawn, that seems silly limiting the gear you can wear and opening yourself up to murder counts, the traps alone are VERY unlikely to kill anyone, you still have to fight, you just strategicly place to help defend/trap (attackers could obviously place them too, stealth in and trap the upper bridge in despise, say, before raiding from the bottom to chase the unsuspecting group up)
Let them "abuse" it switching to their blues so they get stomped and chased off.