I have 100 sneak with all perks excluding the left branch (however, I have tried it with all the left branch perks as well). I'm currently at Knifepoint Ridge, on a quest to stealthily kill all the bandits. Although it's not necessary to kill the bandits stealthily, I choose to do so because I'm a stealth character.
The problem is that whenever I sneak up behind a bandit and cut his/her throat stealthily with muffled boots, stealth rings and necklaces with 100 sneak the sleeping/awake bandits still manage to 'hear' something and say "What was that?" or something along those lines and follows up by detecting me. This has never seemed to happen before. Any advice?