I'm a bit ignorant of smart contracts and I'm not a lawyer, but presumably the service provider would have to take whatever action would invalidate the subscription.
It gets weird with escrow though, because it's possible the law could treat money in escrow (like in a contract account) as already prepaid- if you wrote a contract to be paid every month for 12 months provided that a given key to a service stated valid and funded the escrow for the 12 months, it's possible the court would rule that you bought 12 months of a product, not a subscription.
It gets weird with escrow though, because it's possible the law could treat money in escrow (like in a contract account) as already prepaid- if you wrote a contract to be paid every month for 12 months provided that a given key to a service stated valid and funded the escrow for the 12 months, it's possible the court would rule that you bought 12 months of a product, not a subscription.
I'm not aware if this has been litigated.