[perlgeek]

There are at least two enforcement mechanisms:

* Governments can reach Apple and Google, and thus force them to remove the apps from their app stores.

* Diplomacy. EU and USA will have a lot of negotiation to do pretty soon. USA doesn't like how EU handles big tech and privacy. EU doesn't like how USA's preferred treatment of domestic electric cars in the "inflation reduction" act that went into effect a few days ago. If Meta pulls out of EU to dodge enforcement, the EU diplomats will surely bring that up, and work a solution into whatever treaty comes out of this.