You're probably thinking of activating for supercharger access. Tesla may not let vehicles connect to their superchargers if they've been reported as written off. It also won't be able to connect to Tesla's servers for OTA software updates, etc.

If you can prove that the vehicle has been appropriately repaired (by a qualified body shop, since it's a safety issue in the case of structural damage), it can be re-activated.

But Tesla does not remotely disable vehicles or anything like that. Even if it's been written off, theres nothing to prevent it being driven just like any normal car once repaired.

This could be because of the packaged services that come with the Tesla?