THIS I brought up earlier on the discord - the thief event should only release 1. It was blended into another result in the code at some point. Not going to point fingers at who made this choice nor be too loud about it since I'm trying to be a more humble elder, but I think it's too much too. I suppose a thieves DEN is REALLY a den right now. And yeah that can be very very VERY bad as far as a result.
Obviously, this is a very good reason to value using specifically recon units for unveiling goodies. No bad results.
As a mod goal, I WANT to make goodies possible to slowly respawn, numerous types of new ones for what you'd find later on different maps, the result of collapsed cities, things like that, and then also give us the ability to rate the results on a value scale AND then give recon units the ability to not just say NO BAD results entirely, but get promos and modifiers from things like traits and maybe even civic choices (player level stuff) that make it so they can upgrade or downgrade likely results when they uncover goodies, as well as give to some units ways to DOWNGRADE results - your own barbaric clubmen are probably going to spawn angry tribesmen for example. This might even open up some USE for a diplomat unit to begin with that REALLY specializes in this kind of thing.