Well, yes, it's not game breaking or anything but a little bit sad.

Back in the day me and friends would just cover the entrance to Seagrave Holme's stall (as his was the tightest) in mines and watch as he casually walked into them and, in the funniest moment, simply vanished and not a trace of him could be found. Well I recently bought Fallout 3 game of the year edition on steam and decided after doing most of the quests to go back for nostalgia's sake and blast Seagrave to kingdom come, only this time he walked right over the mines without setting them off. Frustrated, I set mines in front of other npcs in the marketplace only to realize that they didnt set them off either. I was confused, because I'd used mines against enemies with no problem. I tested mines on non-hostile npcs in Tenpenny Tower and they blew up as normal, as they should, when any npc besides the player walks over them.

I am playing with some mods, although its simply a replacer for the vanilla gunfire sounds.

Edit: Tested paradise falls, where they still blow up as normal, and The Citadel, where they don't blow up. Will test without any mods

Edit: Tested without mods, no change.