I am confused by this question, if you forward a port then the only device you should be interested in is the device you are forwarding to surely? If you are worried about devices on your network, then surely since they are already on the network side of the router and so if they were going to do something nefarious then opening a port is the least of your worries.
Honestly trying to understand the point you were trying making.
I presume this is in jest, but to be honest I feel like there is less risk of bad operators consuming my computing power and data when pirating than using legit services these days (ads, marketing, poor software etc…). I actually pirate content that I pay for as it gets all my content into a single location, and easily tracks what I have watched, and is better for taking it offline.