Curious. Can you explain how?
If you're really interested, I wrote a paper in grad school about deck shuffling as it relates to card randomization (see attachment). One way to measure a deck's randomness is to count the number of rising sequences in the deck. If you were to place the cards in order, and numbered them 1 through 52, then riffle shuffled the deck one time and checked the order of the cards, you might find that they are ordered something like this:
27 28 29
1 2 30 31
3 4 32
5 33
6
34
7 35
8 36
9 37
10 38
11 39
12 13
14 40
15 41
16 17 42 43
18 44
19 20 45
46 47 48 49
21 50 51
22 23 24 25 52
26
In the above deck, you can clearly see the two "rising sequences" with the first starting at 27,28,29 and going up to 52 and the second starting at 1,2 and going up through 26. This deck would obviously be extremely exploitable as it's only been shuffled once, but it's helpful for understanding how randomness manifests itself in a deck. The paper I wrote below goes into greater detail, with plotted distributions and a fair bit of coding, about the rising sequence distributions in randomized decks. In short, if you were to take 10,000 completely randomized decks, and counted the number of rising sequences found in each deck, you would find that there were 26.5 rising sequences on average, with a standard deviation of 2.1.
In the 'Shuffle Tech Shuffler' video below where they demo the machine and show the deck after it has been shuffled (starting at 2:00), pay attention to the distribution of the clubs. You'll notice that the deck has 6c7c out front, then you don't see another club until the back half of the deck where you find a few more sequences (TcQc, 4c5c, 8c9c), and that's just from what we can see. You'll also notice the clustering of other suits as he passes through the deck. There are quite a few cards that we can't see as he's just quickly running through the deck though. He seems to think the results are good here and is showing the "randomized" deck that it produced, but someone knowing what to pay attention to could take advantage of this shuffle. Magicians use rising sequences to their advantage when performing card tricks.
You wouldn't be able to gain a huge edge, but you could gain a measurable one. Imagine if you knew that a deck was perfectly ordered prior to the shuffle, and you knew the shuffle resulted in chunked distributions like you see in this video. You could exploit the deck by knowing that straight draws and flush draws would come in at a higher frequency than they would if the deck were in truly random order. Two hearts on the flop would yield a higher probability of being followed by third heart in a deck with too few rising sequences than they would in a deck with 26 rising sequences.
