For better or worse, people tend to have various adhoc, unpuppetized scripts in their mwmaint home directories. When a new mwmaint server is set up, we typically rsync home dirs over, but that's a one time operation. It would be smoother if we just copied everything over before or right after the switchover process so aside from the hostname change, everything is basically the same.
Even though I wrote "before" in the description, I think it could happen right afterwards too, as a 08 or 09 cookbook.