I've never had an issue with my Tesco Metro but on Friday it was frankly ridiculous. Nobody was taking any notice of the one-way system, so much so that I actually spoke to (2m apart of course) a member of staff to ask them to get a supervisor/manager to make an announcement because it was silly.
The worst for me is the old dears, who seem blissfully unaware of what is actually going on at the moment, despite having to queue to get into the store. One old dear in front of me, who scarily reminded me of Daisy from Keeping Up Appearances with her shopping trolley, entered one aisle the wrong way, and I politely informed her and pointed to the arrows to say she was going the wrong way. Her reply was 'oh'. On to the next aisle, she did exactly the same thing. I get some people suffer from a little confusion but this was sheer ignorance.
Staff regularly ignore the arrows too.
Maybe she genuinely did forget things, what do you expect the old dear to do? Go all the way around and start again therefore taking up a lot more time and holding people up due to the one in, one out policy? Forget the stuff she needed and go home? Go back outside and queue again for her sins?
Yes, the arrows are there for good reason but nobody is perfect, especially right now. I've seen it happen enough myself over the last few weeks, they go the wrong way but to their credit try to maintain distance and there is next to no risk from walking past. The worst people in all of this are those displaying your behaviour and trying to self police everything, in nearly all cases with absolutely no need to do so because nobody was doing anything wrong but they just can't help themselves.
Maybe i'm too old fashioned but if I saw an 'old dear' as you have described i'd be asking if I could help (within reason given the circumstances) not telling her what the rules are.