I have a user who has watched Bedtime Stories with Adam Sandler 13 times in a month and I am starting to get concerned. I try to mind my own business with what people watch but when the stats say that it is the most watched movie and there is only one user that watched it, you start to get curious.
But you are creeping on how often they watch a thing. Monitoring it and keeping it a secret from them seems like the worst of the available options to me.
Ignorance is often confused for malicious intent. This person knows the user wants privacy, but it never occurred to them to tell the user where their privacy ends.
He could write a EULA, but this is a private Plex server; why would he need one until privacy becomes a concern?
It is one of those things you don’t really think about until it pops up.