Bastid said:
Even if I was aware of someone who did that all the time and even if I do not think it is right who am I to tell him that what he is doing is wrong.
Gus my friend,
This thread (and its ever-growing family) is precisely about what we (whether we be makers, collectors or dealers) think is "right" when it comes to pre-selling. Expressing an opinion about that is not the same thing as telling a maker what to do (or not to do) with his knives. As has been often said before, makers are free to do what they want with their knives, and are free to accept all, part or absolutely none of anything that has been said here.
While we're sharing anecdotes, here's one of mine.
And no, I'm not going to name names, so don't ask.

But this isn't second-hand, I was there.
I was among the first dozen people through the door at a knife show. One of my very first stops was at the table of Maker X - one of those aforementioned in-demand makers. To my surprise (and the surprise of a few others), the table was empty - as in no maker, no knives, no nothing. About an hour goes by and I've cruised by the table a few times and picked up the word from a few hopefuls hanging around that Maker X is running late but will be attending.
More time passes, and I've successfully emptied my pockets of anything even closely resembling cash.

I happen to spot Maker X making a bustling belated entry. Though I no longer have any dough I still feel compelled to rush over to his table and I'm at the very front of a small crowd that has quickly gathered. While Maker X's capable assistant sets out the (8 or so) knives he is passing up from a duffle bag, an internet retailer approches him behind the table and has a very short conversation wherein both wisper, look meaningfully toward his table and nod. Dealer quickly departs and Maker X turns toward a fellow who has picked up a beautiful knife from the table and is beaming with anticipation. "How much does this one run?" he asks. Maker X "Um, it's sold. They're all sold."
Now I wasn't privy to the conversation but 5 of those knives appeared on the dealer's site two weeks later. Maybe the dealer had pre-ordered all five and was simply taking delivery. Maybe he had bought all 8 on the spot, sold 3 at the show and so "only" 5 made it to his web site. They sure didn't last long there either.
Now, as I said, I wasn't in position to buy anything - I was lucky to be able to buy dinner that night - but there were some SERIOUSLY unhappy campers in that group.
Cheers,
Roger