Developers will be required to disclose if their game uses kernel anti-cheat. This applies to both new games and existing games. Non-kernel anti-cheat is encouraged to be disclosed as well, but it’s only mandatory for developers to declare if they’re using kernel anti-cheat for the time being.
It’s worth mentioning that many games use kernel anti-cheat on windows, but only use user space anti-cheat on Steam Deck and Linux.
Hmm, you have uncovered a problem with both of our ideas. Steam’s leverage is reduced after they have deposited sales proceeds, and is gone after the publisher isn’t selling games on the platform any longer.
(I’m griping about Rockstar specifically but my point is still flawed in the general case.)
Add a clause to the contract between Steam and the developer requiring the dev to reimburse Steam for refunds due to post-sale changes (ie, from that specific ‘accept, decline, refund’ option). If the dev doesn’t pay the bill, Steam can use the breach of contract as leverage.