It does, in a way, you can't buy more than 2. So reserving more than 2 would be an abuse of the system, and as posted a few posts back, Apple do reserve the right to refuse service to people they feel are abusing the system.
Of course, it's everyone's own choice how they reserve, but from reading here and elsewhere, people putting stupid numbers of reservations in at multiple stores seem to get nothing or very little, especially in comparison to people only reserving one.
If it was anything goes, wouldn't the 15 reservations at 2 or 3 locations a day person have far more chance of being successful than the 1 reservation at 1 location person?
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It's always been on a waiting list, I'd be surprised if that's changed.
Stock arrives in the store, salesman starts phoning down the list of people waiting. When there is more stock than waiting list, they offer the balance to walk-ins.