I'd imagine it depends on what granularity "interaction" means:
1. Do you have a chatbox/channel in-game?
2. Can you plug-in usernames/passwords to login to your game accounts?
3. Is your game account tied to social networks etc?
34. If you purchased the game outside of the streaming company and had that tied to a credit card etc then can a notorious game streamed through the app make you inadvertently rack up charges on that card?
I'm just spit-balling here. These are the top attack vectors that come to mind. IDK, maybe I'm thinking wayyyyy outta the box here.