I think their most puzzling "mistake", particularly if Angela Ahrendts wants to get rid of the lines and promote SMART online ordering, is the failure to set up the try on appointments at least a week in advance of the opportunity to preorder. This would prevent so many returns or Ebay and CL resales of watches that turned out to be a poor fit. It would have cut down drastically a lot the ordering of multiple watches on the part of the undecided.
I would have thought this would occur to them after the same thing happened with the consumers being torn between iPhone 6 and 6 Plus.
But maybe they don't care about that and in fact like how the ordering of multiple devices by the undecided helps inflate their numbers for the announcement of preorder volumes.
If they value that above efficiently matching supply and demand...well...