Yes, that chance is real. But let's face it, there's also the chance that someone who didn't rush to go there gets run over by a mom trying to rush her child to the emergency room.
Or a blackout disabling Applestores to handle registers.
As I wrote above: I don't quite get the reason for those starting times and frankly I have no idea how stores like Gravis, Mediamarkt, Saturn and the like plan to keep people from creating a huuuuge mess in the store while waiting in uncoordinated piles for them to take the iPads from their storage into the sales area.
But it is Apples prerogative to sell when they want and if the resellers don't just tell Apple to pi** off, I suspect they expect some side-business out of the deal.
If I were a Saturn Store Manager, I'd probably skip on selling the iPad on launch, because the expected mess in my store-rooms would far exceed every possible money I make with them. I cannot imagine the prices for Resellers to be so fantastic that it can make up for the to-be-expected problems.
Just imagine the store might have to hire extra security to protect the Apple-sales-area in their store. No way the 20 iPads each store might get to sell can make up for the cost of that, and I highly doubt everyone there for an iPad also purchases 20 other items to create some kind of revenue for the store.