The numbing traps passive text reads:
Enemies you Slow or hit with Fan of Knives, Spike Trap, Caltrops, Grenades, and Sentry fire have their damage reduced by 25% for 3 seconds.
Let's say you're in a game with 4 Demon Hunters, all running the numbing traps passive. Would the damage reduction from these passives stack? If so, I'm assuming they stack multiplicatively.