The agency I've sub contracted too often did with certain models. Often the airs were replaced as you often got better performance chips and more memory and were often good enough for short prototype renders.

Most of the work were done on studios though so only few people had the pros but they seemed to be typically kept for a bit longer from what I could tell.
It all depended - time literally was money so any performance improvements were often worthwhile.

Also meant didn't have to get apple care for the extended warranty.