https://www.theverge.com/2019/1/15/18184131/roku-auto-sign-out-mode-airbnb-hosts

Roku just introduced Auto Sign Out Mode, which lets people sign onto your device and get logged out automatically. Say you have guests over, but they have their own logins to streaming services and a tendency to forget to log out, they’ll now be able to set a date when those credentials automatically expire from your device. This especially seems to make sense for Airbnb hosts who may have a rotating list of guests scheduled to visit, all of whom may have their own streaming services they’d like to log into.

The mode basically prevents you from being able to mooch off a house guest’s Netflix subscription and mess with their algorithmically determined recommendations or cause their screens not to play if they’re on a lower-tier subscription with stream limits. You can toggle Auto Sign Out Mode on or off in Settings under System, so you could also keep it off if it’s unwanted.