Tip of the iceburg...to coin a phrase....and not picking on Tesco in particular.

I've been dealing with Tescos, Asda and Morrisons since 1972 (when Asda had 5 stores, including the original in Pudsey, and I used to call on THE Mr. Morrison at his first store at John St in Bradford) and I know their business philosophy pretty well.
Asda of course was started by Associated Dairies (a Hull-based company I seem to recall)...milk processing and door-step delivery...remember that ?
The first Asdas would have made Lidls look like posh Waitroses.

Yes I am cynical, based on knowledge and experience of sales and marketing in the grocery sector as well as others in the big bad world of commerce.

These businesses are rampant and rapacious in their urge to expand or maintain their 'market share'.
Wherever profit can be made it will be, and if that means bending or breaking rules, then that will be done too...behind the veneer of 'compliance'.