Actually, the SA's I talked to yesterday both expressed frustration (in a very mild and professional manner, of course) because much of their stock was already sold out, and they expect customers to be disappointed or angry on Friday. (Doesn't sound like stock being held back!). I think the new pre-sale opportunity for *all* cardholders has created a bigger rush than they expected. I don't envy those SA's! Be nice to them!!
And yes, my advice would also be to order online, and to check back frequently, since there will be a LOT of return processing in the coming weeks, so stuff that's out of stock one week might well be available again the next week.