The biggest problem isn’t users trusting mints, it’s the other way around, mints trusting users. If you run a mint as intended by Cashu lore you have to accept there will be money launders and other criminals using your mint. Because there is no way to prevent them and no way to know if they are using or have used your mint, so the only sensible default assumption is that they are. Setting the default as they aren’t until proven otherwise is nonsense, since there is no “proven otherwise”. No regulator with a brain is not going to side-eye you.
The only way around this is to use a mint in a way not intended by the lore, for example ID us users at the app level, but then you have to ask why are you using cashu in the first place?