Do you like to pay fish prices when you're buying ice? Some people are happy to sell you ice at $15 per pound. An investigation of people selling fish packed in ice, and charging you for the ice, found the deceptive practice is common.
It's bad enough that you might want cod and get pollock instead. Adding insult to injury, you might get 10 ounces of pollock when you pay for 12 ounces of cod. Ouch.