Steam Family Sharing now requires the primary account holder to identify potential users, to reduce the chance of bans caused by your roommate’s antics.
The system still allows you to offer your Steam library to those you share hardware with, but you’ll now need to identify your friends and family by Steam ID via two-factor authentication.
Unauthorised users who log into your machine can still request access, so it shouldn’t be too much of a hassle to organise.
“This allows lenders more control while reducing the risk of VAC or other bans resulting from an unknown user accessing and abusing shared games on an authorised machine,” Valve wrote in an update on the Steam Family Sharing beta hub.
Steam Family Sharing supports up to ten accounts on ten machines, making it pretty ideal for housemates and family members who use more than one computer, share computers, or want to pool their games. It’s currently in closed beta testing.