It's quite common in my local Tesco's in Bishops Stortford for people to be coming the 'wrong' way, in fact it seems to be a bit of a free-for-all with people doing all sorts of daft things. The one that really annoys me is where they bump across the parking bays from one lane to another - it just seems to be that people just don't give a damn about any 'rules' and selfishly think they can do as they like.
In the past I've told people they are going the wrong way - in a wanting to be helpful way - and been met with complete incredulity that someone should tell them they're in the wrong and some abuse.
I've now decided that 'giving advice' to others is not worth it, so I'm now prepared for whatever idiotic thing they might be doing and just ignore it with a bit of a withering resigned look.
Incidentally, I think Waitrose offering free coffee in their stores is the stupidest gimmick ever - my local Waitrose is only small and to have the foyer area crowded with freeloaders puts me right off.