This happened over a decade ago. I was a contractor doing IT work at TMMC (Toyota Motor Manufacturing Canada). The plant has two shifts, a day shift from 700-330, and a night shift from 600-230 (I might be slightly off). Teams run two weeks on one shift, then switch to two weeks on the other shift. Also note that the plant is non-unionized.
The issue is Halloween. Because a year takes 52 weeks + 1 day, it meant that members would end up working Halloween 5 years in a row. IOW, if you have say a 6 year old, the (usually father) would be unable to walk them around the neighborhood until the were 11. Not surprisingly that meant a LOT of night shift members called in sick each October 31st.
So one year, to combat this, management decided to hire a private investigator to follow around some of the team members and capture them faking calling in sick. The next day 4 team members were called into the office and fired on the spot.
They probably could have gotten away with it except one of the 4 was considered a model employee, always showing leadership, never calling in sick otherwise, and being very popular with everyone. People were furious. Suddenly productivity in the factory collapsed. It was made clear, nobody was doing overtime, and the line was going to be run super slow until they were re-hired. Management tried strong arming the team members but it was pretty obvious where things were headed. After a couple of days the 4 fired team members were back on the job, things were cooled down after a mea culpa, and a compromise was made that on October 31st, the night shift would start late and do a 9-530 shift. A simple solution to the problem.
I think that was the closest that factory ever got to joining a union. If the CAW had been aware they could have signed everyone up that day.