there's a number of games where this would be handy as currently i would have to manually disable network adaptor after opening the game.
im not a coder but could you find the game/service i.e steams connection and just fiddle with it like redirecting it to a non-funtional port/proxy?
essentially just firewalling/blocking those particular connections
or to make it simpler do it to everything but the trainer Auth server and the mobile app's config.
Agreed it would be Nice to also set that up, but the only kicker is that I am seeing alot of game titles mostly Bethesda and Rockstar are kinda doing a Verification via Internet Connection to get access to game content.
Or even better the option to keep running Ghost Recon Breakpoint with the Kill switch enabled would be nice too but apparently that requires internet connection to upload your character data to the server's during changes and adjustments stuff.
But it worth exploring on how well it can be applied or depends on how complex it can be coded.
Do we need a Kill switch?
Yes, for the number of times some games will attempt to Pull data from Singleplayer games it wouldn’t hurt to Have it and not need it, Rather than Not have it and need it.