Depends on the bargaining unit, but you're right. My plant would agree with you, but some locals will really fight to the death on things that (imo) they shouldn't.
The double edged Union sword: you can protect and fight for those that deserve it, but it opens you up to almost having to do the same for those that don't, unfortunately.
I grew up in a UAW family, my grandfather was a committeeman and I'm 4th Gen GM employee, so I know how it goes- although I'm the first to be non-union, so not as well as Mitdr does.