Forum:Why do the talon mercs always detect me

I've been trying to place a grenade in a talon mercs pocket but when I get about 10 feet near them it always turns from hidden to caution.I'm even wearing chinese stealth armor and have 100 sneak skill along with the silent running perk.What i'm getting at is feral reavers and even super mutant overlords don't detect me.It's the same with regulators why do they always detect me.