If I knew with confidence that what they were doing wasn't harming anyone, and wasn't gang related bullshit I'd just look the other way. The department can't fault you for "missing" things.

Example would be catching someone tattooing. This often ended up with time in solitary. But if it wasn't a gang tat, and the inmates weren't dicks about being caught/immediately flushing all the evidence I'd just kick the tattoo artist out of the cell and the half finished tattoo is enough punishment. They'll get it finished one way or another but it's more funny to me than sending them to the hole, and they appreciate it most of the time. If my supervisor happened to be with me, or watching me though, you were cooked. Most understood the fact that I would protect my income over them being as I wouldn't give a fuck literally any other time, but my hands have been tied more than once when shit should have slid by.