Doesn't really need to be "strict" in this case. Texts could come back with a context from the recipient. Say you text someone, they're driving, you get a status of "In motion," or "In a movie," or something based on the data coming back from the phone.

They're not necessarily unable to respond to you, as in not locked out of their phone by the carrier, but the carrier knows they're moving at 30+mph, and gives that data to the sender.

The majority of people who just want to live safe, comfortable, predictable lives have a right to use government to protect themselves from the (very substantial) minority of people who are shitbags.