Sometimes they won't get fired even if they put in less than the bare minimum. I know a number of people who have worked in the Detroit area auto industry and they tell stories of hourly workers who kept their jobs after being caught literally sleeping or drunk on the clock. Union leadership doesn't seem to understand that by defending those slackers they might get a temporary "win" and stick it to management, but ultimately it just encourages management to move production elsewhere.

Agreed about the shortsightedness of unions.