Oh dear, she really has made a rod for her own back hasn't she? Before I continue I will point out that I do not support some of the kinds of threats that have been made, they should be dealt with as all threats made online.
However most of the rest of the criticism this shop owner has attracted is well justified. One sign during the mandatory period would have been more than enough, but this owner has decided to go full loco with it, made all the worse for having dummies alongside "for those that want to argue". It does make me wonder if there is something more going on here, and a couple of points I picked up on make me think there is. Firstly
Now while it was true that supermarkets did run out of things briefly where some smaller stores didn't, making the claim that she could get stuff that supermarkets couldn't, hmmmm. This makes me think that she has a bit of an axe to grind. I wouldn't be surprised to find that there has been a dispute with the local council over planning for a supermarket in the area, or with another local business. But what really stands out is this:
Ah ha! So its not the locals, its the not-locals, coming to their shop, touching the precious things.... (For those unaware, this is a reference to a couple of characters from the BBCs dark comedy League of Gentleman)
Maybe the signs aren't there for the locals, I'm sure if Mavis from down the road walked in having forgotten her mask would not be marched out by the owner. A stranger however.... Remind me never to go to North Cave!