As Advantage gamblers, we need to question things, and ask the next question.
This can be tiring, as there are fewer resources u can trust, and fewer knowledgeable people, willing to share info .. but, still, it needs to be done.
A while ago, my local casino, banned the use of cell-phones, from the poker table. I thought they were just being miserable, as they already had policies of no food at table, no free drinks, and were in the throws of putting in policies, which would lead to the room closing, organically.
Last yr, it became public knowledge, that it was possible to 'edge-sort' playing cards, and skilled professionals, could recognise a cards value, from the careful observation of the back of the card.
I just came across a video, where a hacked android phone, could observe the sides of a randomly shuffled deck, and accurately predict the top 2 cards of the deck.
The presenter has an irritating french-Canadian accent, but, if u can get past it, the power of the program being sold, was pretty impressive. (Basically, it uses the phones in-built camera, to match previous pictures, of the edge of the deck. - Ok, so, u need to get hold of the deck .. but, for home games etc, this would be trivial)
Asking the next question .. if it can spot a card, from the top of a deck, there is no reason it couldn't reveal the ranking, of any casino game, where the hold-card is dealt face down (to the dealer).
There are quite a few casino games like this .. I wonder how much, they have got away with. $3000 or so, would be a fairly cheap investment .. if, u couldnt prep your own phone.