You might be completely right.
But *why not* wear a mask, if it's not a big ask? Disabilities etc aside, I'm not hearing any particularly convincing reasons.
There has been a lot of publicity relating to the risk of incorrectly worn and used masks increasing the risk of transmitting germs. To me that’s quite a convincing reasonespecially when one observes how many people are doing wrong things with their masks on transport. I’d think this could be even more of an issue in shops if people take their mask off between shops, plus there’s the added issue that people will likely be touching things in shops.
It might work if people had a robust regime for fitting, wearing and removing masks, however I simply don’t think this is going to happen.
But for this reason I might be inclined to take your view that in the current situation it’s probably worthwhile as a shot to nothing, subject to some checks to ensure it’s reviewed on a pretty constant basis to stop it dragging out and becoming some kind of expected norm in public, as opposed to a strictly controlled emergency measure. However when combined with the flaky evidence as to effectiveness this tips the balance away from it.
I have also experienced first-hand how correct use is virtually impossible in a railway setting, so can fully understand how this is likely to be an issue elsewhere too.