I was having a weird issue with CrashPlan, in which Munki was blocking CrashPlan from uninstalling because CrashPlan.app was supposedly running (the actual app wasn’t running‐just a CrashPlan-initiated launch daemon). Unfortunately, I didn’t actually read the documentation on blocking applications, because there is, in fact, a different between not specifying a blocking application and specifying no blocking applications.

If you don’t have blocking applications specified, Munki will still block anything in the installs list.

If, however, you have an empty blocking_applications array, nothing will block the uninstall.