I don't understand this media campaign against shrinkflation, it's not Coca-Cola and Heinz' fault if inflation exists. Is it more egregious if price rises from 90 cents for a 100g ketchup bottle to 90 cents per 90g bottle, instead of 1 dollar per 100g bottle?
It even has the added benefit of people eating less pre-packaged crap.
As others have said in this thread, if you want to be honest with costumers make supermarkets add price/100g next to the price label.