Apparently you could weigh the decks to find out which have loot cards. All those cases and packs of cards I bought on ebay with a very low loot card drop rate are starting to make sense.

All decks had the same number of cards, just that loot cards contained the scratch-off stuff, which made them weigh different. Now that they started adding the scratch-off stuff to the non-winning extra card as well, they can no longer weigh the packs to tell if they have loot.
http://wowtcg.cryptozoic.com/live-co...reasure-chests

These were not just at eBay, Target and Walmart also sold decks and cases from 3rd party companies.

Yesterday I bought 10 decks and received 6 loot cards, simply amazing.
4 x Sand Scarab
1 x Bloat the Bubble Fish
1 x Throwing Starfish

Anyone want a free Sand Scarab pet?