I once watched one do a stealth operation to catch people fishing on a lake without a permit.

He got there well before dawn, slipped his boat into the lake and hid in the shadow of a ledge among the reeds. He'd wait until a boat would get way out into the middle of the lake and get settled in. After they'd make a few casts and get real comfortable, he'd come tearing out like a bat out of hell and swoop down on them. Then he'd write them a citation and force them to leave. He even took one guy's boat!

Rinse and repeat. It was the most entertaining ending to an insomnia-plagued night I've ever had!