Disclaimer -> NAL. I think it's extraordinarily rare for rulings to have retroactive effect. If sth was legal when you did it, you can't be held to account if that thing becomes illegal later on. That would open up all kinds of bad probs. Editing to add, your ability to follow the law today, can't require that you successfully predict future laws or future court decisions.

But geo-fence data already collected would fall under this decision in the future. So let's say there's 2024 data. Data still exists on some Google server. Now it's 2028. Cops would need a warrant to obtain the 2024 data in 2028.

That's my understanding. Again NAL.