I recently had an experience with huge battery drain from an app that "ran away." It was fixed by restarting the phone. From my experience, BB phones need to be restarted regularly to "behave well." I used to have a memory app in OS6/7 that auto-restarted my phone daily.
I know the current OS version doesn't allow auto-start of apps (with head) after a phone restart. Well, will just have to keep fingers crossed that some developers or BB will address that soon.