They well could. It's based on numbers, and not everyone in connecting cabins is traveling together - especially on the Dream class when it seems a LOT harder to find NON-connecting cabins. My guess is there is *probably* more of a possibility that cabins may be in different muster stations on the Classics since connecting doors were added in dry dock.
Of course, Disney does require that there be an adult booked into each cabin, so...that's how they truly CAN put connecting cabins in different muster stations. While they may not care who sleeps where, in the unlikely event of an emergency, each person WOULD be required to go to their assigned muster station no matter where they were sleeping.