What does this mean....

It means Apple reserves the right to butt **** you. Without lube.

 

The English seems clear, plain and simple. But to make it clearer:

If you are 1 second late Apple will sell your iPhone to someone else, you won't get them and you won't be able to complain. Get there on time. Or better early.

 

My understanding is this:

There are two separate pools of stock at an Apple Store. Units for people with reservation and whatever remaining number of units for walk-ins.

You are getting into the line with reservation, and still subject to the availability within that group. Let's say one store got 500 units in stock. The reservation list for that store has 520 names. Then you'll have to pickup before they run out of stock. If you don't have the reservation, then you are F'd.

If the store got 540 units (they probably don't know the exact # until they receive the loads), you are all good as long as you claim yours within the day. Walk-in people will fight over the 20 non-reserved units left.

Makes sense?