I propose a way to keep your eyes on a player (only one at any time though!) as to make it much harder for him to steal from you. This would obviously make sense from a real world perspective (which isnt always a good thing) but i thought of it because of a situation that is just dumb right now:
I have some kid running around in vault city thieving and not caring whether he gets caught or not.. Its just for kicks.. Thing is he will get your item now and then and once he dies its as good as gone.. Then when he dies he just comes back and does it again. Its just dumb because i KNOW what hes going to do but i cant prevent it in ANY way.. thats dumb.. same would go for a known master thief. If i know somebody is going to steal from me i shouldnt have to leave the city

Now this kind of thieving behavior could be exploited (depending on your personal definition) but really im proposing just because it makes sense to me at this moment (I havnt thought to much about it)
So if you can point out a reason to not do it please do so ^^
Btw if thieves work in teams well to bad... thats how things happen in real life too

Also sneaking would also negate being able to "Keep your eyes On" of course