Ehh... yes, it was said many times, it is bugged. You can steal/plant items with your main character, because you don't need to be afraid. You don't getting unprotection by this. Probably, will be fixed at the next update... I hope.
they do have to be afraid, a eye crit from a crappy .44 pistol or a double shotgun blast can end you if you're low on health points. and since i only PK in NCR... i've found a new use for all the brave new pick pockets i see running around... *orders a few large boxes full of 90% det shotguns* ^,..,^
even if you get killed by the guards its still funny to watch them go splat..
but yeah, i think they should at least make them killable again, and change the messages, since the "interested" message does not mean they're flagged, it means they're looking last time i checked.
-Ulrek-