Light Step/J.E. Sawyer's Fallout RPG
Fallout 2 and Fallout Tactics
You are agile, lucky, and always careful. This perk halves your chances of setting off a trap.”— In-game description, Fallout 2
This perk is broken in Fallout 2. The 50% reduction doesn't affect every mine in the game, just the ones at Sierra Army Depot. It's slightly more useful in Tactics, assuming the player doesn't just disarm the minefield with a few shotgun rounds.
Fallout 3 and Fallout: New Vegas
Traps affected include mines, tripwires, pressure plates and bear traps. Traps such as explosive baby carriages still go off, as do grenade bouquets if the player makes contact with the grenades, or shoots them.
J.E. Sawyer's Fallout Role-Playing Game
Maybe it was the landmine that almost blew your leg off, or maybe it was the sight of your buddy in pieces next to you. Whatever the cause, when you meet the triggering criteria for a landmine, door bomb, or steel trap, there is a 4 in 20 chance per rank that it fails to go off anyway.”
Each rank reduces the chance for a proximity-based trap to go off by 20% (60% total).