The team at Stadia have added a new feature, that allows players to join select games without the need for an invite.
This means that should you be playing Far Cry 6 (One of the supported games) for example, you’re friend will be able to jump in with you, just by joining via your Stadia profile page.
It’s a nice feature to add, and will make joining friends in-game, much simpler.
You can read more regarding the process for enabling / disabling below:
Let players join your multiplayer game without an invite
Multiplayer games like Far Cry 6 let other players join your game directly from your profile without an invite from you. This feature, available only in select games, is off by default.
To enable it, go into your privacy settings under “Your activity” and “Current game” , then turn on Join your current game. To change who can join games from your profile, choose All players or Friends. Only players in the group you select will be able to join your game.
Stop players from joining
If you don’t want other players to join your game without an invite, go into your privacy settings under “Your activity”,
“Current game” then turn off Join your current game. You can also select Only you or Private in the dropdown menu.