Unity is going to charge for installations of games using their engine

[Hiku]

NEW - I got a major update from Unity about their new fees
- Unity "regrouped" and now says ONLY the initial installation of a game triggers a fee
- Demos mostly won't trigger fees
- Devs not on the hook for Game Pass

More here:https://t.co/GCKjEeFtYR

— Stephen Totilo (@stephentotilo) September 13, 2023

Now it's 'only' for the initial install, supposedly.
But like their other explanations, questions of how they're able to discern an initial install from successive ones, seem to come down to "Just trust me, bro".

Is any of this suposed to apply to games already released? Because that would be insane. Imagine signing the contract, and then years later find out you owe them millions because of this new policy they added after the fact.