I also doubt that the watches will sell out in minutes. There is also 14 days between pre-order and launch. If you get your pre-order in there might be a day or two where they are sorting out the global preorders and the delivery where they don't guaranty delivery. But I bet it gets sorted. Remember they had fully functional versions of the watch that looked great nearly six months ago. I don't know when they went into real large scale production, but I think they've had time to stockpile product.
And the price point on this watch means that this is not initially going to sell in the millions. At least I don't think it will. Millions of people won't preorder without seeing this in person. And millions of people can't make it to an apple store on April 10.
Now if there is a line outside stores starting a few days before for people to get to see the watch on April 10, then I think we can safely say that those Apple fans have gone a little crazy. But I guess someone is going to lineup outside the 5th Avenue store in early April and expect to get on TV, which will probably work. Oh well.