Haha, I was just watching a friend play this (still haven't bought it myself, too many games on my "to play" list and not enough free time).
Apparently the obstacles be damned thing applies to knives from kitchens too. I watched him build a kitchen way across the map from the canteen with a maze-like zig-zagging path between the two completely covered in staff-only doors. The prisoners would suddenly start acting strangely and make their way to the canteen and just sit there by the staff-only door until a cook came by, then follow them through a few hundred staff-only doors along the path across the map until making it to the kitchen. Then they'd get a knife and wait by the door again for the next cook making a trip to the canteen, repeating the trip all the way back, then go about their business as if nothing had happened (with their new knife).
It's just another in his long list of attempts at keeping the knives from the prisoners, which all failed miserably (including an attempt with a metal detector that he couldn't get to work). He loaded up and showed me one of his early ones that had led to all his prisoners escaping, as they went for knives to the kitchen that was outside the prison, then suddenly realized they were out and escaped. The cooks never seemed to mind that prisoners were following them outside or getting knives right in front of them, even guards stationed in the kitchen did nothing to stop them. On the one where the prisoners were escaping, guards stationed outside were too slow to actually catch any of the escapees, with them running off right through a bunch of guards before they reacted.
I then watched him build a 5x5 building (walls and a 3x3 area in the center) and pile 20 prisoners into it, then remove the door and wall it off with brick. Soon the prisoners inside were all destroying and fighting and beating each other up (with various weapons they had brought in from outside, ranging from clubs to knives to what looked like glass). But all his guards spazzed out outside the room trying to path to the "escaping" prisoners and he wasn't able to do anything with the next batch of prisoners to arrive.
It looks like a funny game with lots of potential, but it's definitely an alpha with all the bugs. I'll be keeping an eye on this one.