We follow the same as several comments, we set the sysadmins to master and everyone else to tempdb on all servers in all environments from Dev to Live.
We reasoned that tempdb should be available and if it wasnt you probably dont want users connecting and they probably would be having issues if they could
Also that tempdb doesnt get dropped, moved, renamed or restored in the normal course of business.
Sytems get moved from shared instances to dedicated servers.
Applications sometimes update the name of their database on upgrades.
On development and test servers it can be even worse with databases changing often, version numbers on Database names during regression testing, databases getting dropped as no longer used that are the developers default db . I have seen these and more and they were the cause of our choosing to use tempdb when we analysed the cause of the issues and realised we could take action to avoid it.