I'm thinking it would be good if the packaging guidelines highlighted the need to have the rpm scriptlets return 0 exit codes. Some suggestions:
https://fedoraproject.org/wiki/Packaging/Guidelines#Scriptlets
Add || : to the example scriptlet. Have a sentence or two explaining the need to do that.
https://fedoraproject.org/wiki/Packaging:Alternatives
Add || : to the examples.
packaging@lists.fedoraproject.org