Should not be an issue unless CA decides to send enforcement officers door to door to check up on you in which case it would be long past time to move to a different state anyway.
It seems to me that it would be similar to Title 24 enforcement, ie all new construction/remodels must have them. If that is the case, then a large majority are going to do nothing about it. Sure there will be some who are so disgusted by it that they will rip it out and repalce it with another, but most won't.
As for enforcement, not living in CA (thank God), isn't there something in Title 24 that requires home affected by it to be up to code when sold?