I'd amend this to say "A PROPERLY shuffled deck of cards is unique in all human history".
Without proper shuffling, a card deck is like an encryption key with a poor initialization vector -- it's more predictable.
Card decks ship in order, and playing solitaire will potentially put it back in order. Many people don't shuffle properly, so I would hypothesize that the actual set of decks that most people run into are less random.
I concur. Another question to think over is...lets say you hand out a brand new pack of cards which come arranged in a certain order. Now you hand them out to one million people and ask them to rifle shuffle it 'N' times. What are the chances that two of them have it stacked in the same way after they do so? My guess is for low values of 'N', it would not be that uncommon.
Without proper shuffling, a card deck is like an encryption key with a poor initialization vector -- it's more predictable.
Card decks ship in order, and playing solitaire will potentially put it back in order. Many people don't shuffle properly, so I would hypothesize that the actual set of decks that most people run into are less random.