vanilla I didn't say it wasn't legal I said it wouldn't protect you or stop you passing anything to anyone else.
Regardless of the letter of the law, I think we all know that we are not being asked to wear a mask for the decorative effect. How about focusing on being a decent citizen and trying not to spread germs to others ratget than how we can get around a law that is for the good of everyone?
Re efficacy of fabric masks I agree there's not a huge amount of evidence saying they are effective. We know that a single layer of cotton is less than 3% effective as there is a randomised trial about that. Hence why we should be trying hard to use masks that are better quality than that. I'd suggest that the water resistant layer is what makes the difference between the 3% efficacy of a single layer of cotton and the 56% efficacy of surgical masks.