You don't need a dedicate Plex server to pirate. Any bittorrent client will do and people might just be happy using a built in media client. Plus often people are happy to buy systems pre-built (remember the "Kodi Box" craze?). Piracy is a service problem not a price problem so people are willing to pay for systems like this if it's easier than managing subscriptions to multiple services (and the fact it usually works out cheaper to pirate is an added bonus).