If you want to continue using the services, and know about the change, then that's legally, as cited in the actual court documents in OP, an agreement to the new terms.
You cannot cancel a contract for "any reason". In most jurisdictions that will be an unenforceable term.
Usage here being consent, is an unpublished ruling. It does not set precedent, it refers only to these specific circumstances, where clients sought to understand terms before choosing to continue usage.
Legally, usage with foreknowledge, is consent. Usage where you already agreed to terms implicitly, because you sought and understood them beforehand.
It will not always be an agreement to new terms.
> This disposition is not appropriate for publication and is not precedent except as provided by Ninth Circuit Rule 36-3
Vader might say he can change the deal at any point, but consumer law generally requires that what is purchased reflects what is advertised.
If you don't agree to a new set of terms, because the service is changed from what you purchased, then both parties generally should still be party to the previous.
Notification alone, is not enough. Agreement is required.