Again, I don't care about orphans.  In the usual cases people are running code with no concern about what happens in case of forced termination.  The only thing stopping it now is that the code goes out of its way to prevent it (or, alternatively, goes out of its way to force Pool workers to be daemonic).  So, e.g., people publish recipes for replacing multiprocessing.Pool to remove this restriction, like here:

http://stackoverflow.com/questions/6974695/python-process-pool-non-daemonic/8963618#8963618