To expand on that, if half the workers are home and the other half are actually essential the chances that whomever was actually exposed first and brought it to the plant would have actually been working from home is 50% (sort of - not everyone has a similar sphere of contact, and some overlap, and…). More over if the whole state was under a stay-at-home order chances are high that whoever brought it to the plant even if they were essential would not have been exposed to it go up.
So while you can’t say “no wouldn’t have happened with a stay-at-home order in place” it is easy to see why the chance would have gone way down. (not to zero because there is some chance you could draw an unbroken line from a worker to someone who had it before a stay-at-home would likely have been issued that only touches essential workers, or connects people living in the same homes…and someone who worked at the plant could have gotten it from a grocery store worker…)
