When I did expunge(true) on a jboss7 entity, I saw logging of:

    2014-01-28 22:18:47,089 WARN  brooklyn.management.internal.LocalEntityManager@2524e205 call to stop management of unknown entity (already unmanaged?) JBoss7ServerImpl{id=mPXYvab1}; skipping, and all descendants

This is because Entities.destroyCatching will also unmanage. So you want an if-else, to only do the `mgmt.getEntityManager().unmanage(entity)` in the else block.