This is a question more for the devs or people who know how this works (as I have no idea how games run):
According to some blog posts, Subterfuge is 100% deterministic in nature, meaning any game can be easily resimulated over and over without error using the correct seed. This allows devs to observe changes applied, and how it would have affected games in the past (something something divergence?)
I assume that means it should be impossible to modify the game in any way(ie adding drillers) as when the server resimulates the game it will find a discrepancy and notify the devs?
That is a very ingenious way both to troubleshoot and to stop hackers, if that's the case!