For a while now, I've suspected but just now confirmed that after a whole prison shakedown (2381 items/inmates searched), which was performed while they were sleeping (so there was no passing of goods to other inmates) did not reveal any tunnels, even though all of the toilets were searched. I found a few digging tools, so I promptly searched some of cells after the shakedown was over, and it unveiled quite a massive tunnel system underneath 6 or 7 of the cells in that area. There's no way that they could have dug that in literally a few minutes, but the shakedown search (which again, included toilets) did not reveal any tunnels.
Do the toilets have to be searched separately and individually from other things (vs a cell search, or a cell block search, or a shakedown) in order for a tunnel to be revealed? If this is the case, is it considered a bug?