Does anyone else have users watching the same content over and over?
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.
Consider the fact they may be using a 3rd party application, like ErsatzTV or similar, to create a "virtual" tv station that just plays videos in sequence after being added to a channel.
You can always reach out to the user in question if you're concerned though. I generally wouldn't open my plex up to users unless I had regular communication with them anyway, but that's a personal thing I think...
Edit: Another thing to note is that, depending on the user's tech savvyness, they might not be aware that you can see what content they're watching. If you aren't close friends, it might turn them off the service to have an admin approach them about the content that you yourself are hosting. Consider this and really weigh whether it's your own business or not. And obviously, to be clear, you definitely shouldn't be charging for this service so make sure that you're not putting yourself in potential legal problems.