Enforcing sites not calling out to third party data processors via client-side JavaScript is detectable and enforceable, but taking such actions server-side is undetectable (and therefore unenforceable).
If they get caught lying (and that tends to happen in the end) that's another violation that is taken seriously nowadays.
For example, my e-mail server started picking up messages from DELETEDmyname@mydomain.org. Making it pretty clear a company did not respect my wishes to completely delete all data and user account references. They simply changed my email in the DB.