that's all well and good, but I wouldn't buy a pint of milk or a loaf that had todays date on it unless i was using it all today. Be like buying a new full price TV with 1 day warranty left on it.
The problem with dates are the supermarkets, most of there fruit and veg in the uk is nearly bad as it reaches its sell by date. Nothing like as fresh as buying from the market.
My parents had a food shop, and yes the majority of dates are only a guide. The dairy farm they used to buy cream from delivered once a week, over the xmas period they did not deliver in between xmas and new year, the farm just stamped an extra 5 days date on everything.
I used to live on 'out of date' yogurts as a kid, they only go off when the lid starts to bubble, sometimes anything up to 6 weeks after sell buy. These were from farm also, wouldn't want to try it nowadays with a tesco one.