HANDS TO YOURSELF, SNEAK THIEF.
-every guard from lvl15 onwards
Apparently only thieves use sneaking, not helpful law abiding citizens who offer to help the jarl kill off a group of bandits using stealth to gain an advantage over the bandits in their own hideout.
Personally I use my sneak skill for hunting so that I don't scare off my target, but I'm obviously doing that wrong, as every time I walk past hunters on the road, they immediately start shouting and cursing at the animals while trying to shoot them.