Union, non-union, it doesn't make much difference in my opinion. People who are prone to ignore warnings are ubiquitous.
I once designed an operator panel for a rock crushing operation. They had a problem with operators ignoring warnings on the nice new Touch Screen HMI, so the owner wanted an old-fashioned push button panel with red illuminated Push-Pull operators. I set it up so that any time a conveyor or machine ran or stopped out of sequence, ALL of the 48 red lights would flash on the console at a slow strobe rate; so annoying that they would have to pay heed to it.
6 months later I got called out because the PLC was not working. I went through my trouble shooting and found that several of the relay output cards had failed; welded relay contacts. But the failed outputs were only going to the LED pilot lights, how the heck was this happening? I replaced 4 cards, ran the PLC and ALL of the lights were flashing all of the time! Turns out someone had started systems in a different sequence because they felt they knew better than the program I had made (at the very specific instructions of the owner). But of course since it was out of sequence, that made all the lights flash. They had been running it for 6 months like that, just plain wore out the relay outputs!