Wondering about iPad 3 in-store preorder pickup...

For anyone who's done an in-store pickup of a preorder of an Apple device before (i realize it will probably vary between locations), is there a separate line for those who have preordered vs. those who have not? How likely is it that my preorder will be sold off to a non-preorderer (none, i assume)?

Seeing as this is my first launch-day Apple product pickup, I'm fairly nervous about it.