Usually a law is left intentionally vague so that it is difficult to challenge in court. The "details" are left to the unelected bureaucracies to flesh-out in the form of "regulations". It is common for regulations to spell out what businesses must do in order to maintain their licenses, etc, but when it comes to a law directed at individuals, the bureaucrats must be more careful. Thus details of filtering mechanisms, etc as you describe would not be included in the law, but could in theory be included in a regulation. Court challenges would be quick (if the regulations are enforced), and the regulations forced to be changed.rjlittlefield wrote: ↑Wed Jul 15, 2020 7:55 pmIf the law were written by somebody who was careful about what they were doing, it would specify the functional characteristics of the filtering mechanism, and for convenience of enforcement, would also list some specific examples of mechanisms that, in the absence of other evidence, would be legally presumed to either meet or not meet the requirements. Sleeves, handkerchiefs, and fingers would fall in the latter category. If somebody can demonstrate that their fingers are the functional equivalent of several layers of cotton fabric, and that they were using them consistently in that manner, then of course they should be permitted to do that.ray_parkhurst wrote: ↑Wed Jul 15, 2020 6:54 pmedited to add: an actual law might be that "it is illegal to expel air from your mouth or nose such that it can escape into the surrounding airspace unimpeded."
You may have noticed that very few if any of the shutdown orders (including masks, social distancing, etc) are being enforced. Many county Sheriffs are refusing to enforce the orders because they are perceived as unconstitutional, thus much of the compliance has been voluntary, with some amount of "peer pressure" thrown in. The only valid rules are those instituted by stores and other businesses. It's perfectly fine for a business to decide that it will only allow you inside if you are wearing a mask, have a normal temperature, are not coughing, etc.
I've been curious how it would resolve if a law was passed requiring that employees wear masks, and an employee was fired or otherwise reprimanded for not wearing one. I suppose if the company held the position that it's not corporate policy but was only enforced due to the law, the employee would have standing and the law could be challenged. If the company's corporate policy included mask mandates, then I suppose even though the law required it, standing would be questionable.