Now I'll have to admit I didn't know about the auto-aggro volumes before this discussion.
I always just assumed I screw up from time to time, which of course I see now is ludicrous!
While I don't like heavy-handed scripted events in general, I can't complain that they are over-used or overly punishing. If this were a game like Thief or Styx where getting spotted and/or having to kill means failure (in expert) then I too would be pissed, but it isn't. Kill the zeds and move on. People complaining that it wasn't disclosed to them that stealth might not be 100% effective in all circumstances really makes me SMH. I feel like some of you are just trolling at this point. This has turned into a tempest in a teapot. Maybe TFP should add: "Warning, you may be killed by zeds" to every description and every journal entry to prevent any future incidents like this.
Honestly stealth is broken all around. I use the silencer more for effect than because it seems necessary, unlike other zombie games noise doesn't do much and seems to follow very strange rules. If sneaking the arrow in the head won't wake up the zed next to it, if not sneaking it will. That makes sense right?
I haven't delved into POI creation but from this discussion and my own observations, I'm guessing it all has to do with the way the rooms are designed. Sometimes I can run past a building and everything in it aggros. Other times I can tear half the building down before a zed notices.
I seem to remember back before the days of POIs it being more like State of Decay where shooting unsupressed guns brings every zed in the area, and so it was an option of last resort.