I've told this story a million times here. But why not again? A friend's dad was a lower level executive for Ford. He worked in Mexico. He said they had to have an extensive Temporary Part Time staff available due to all of the call-ins and no shows for shifts. He even said at times there were so many call-ins they didn't have enough staff to cover the shift and would bring in guys hanging around the gates or "friends of friends" to fill the shifts. Is it still like this today? I have no idea. But what this means is that with all the call-ins, you have replacement workers trying to find their way through a shift and not working a "regular" job on the line they are accustomed to....in which case quality will suffer.
