Quoto un post che mi pare spieghi bene la cosa:
Cita:
Booster packs are filled by machines, and for machines, creating true randomness is hard. Very hard. Especially when you're dealing with objects that need to be physically manipulated into the required order. And even if you could achieve true randomness, it isn't exactly desireable when creating booster packs--it leads to things like no-mythic boxes, or boxes with ten of the same rare, or similar ridiculous things.
So booster packs aren't truly randomized; they're only pseudo-random. On a small-to-medium scale, it appears pretty random, sure. But on a much, much larger scale, patterns can be detected. And once those patterns are discovered and sufficiently understood, they can be exploited on the smaller scale to know the likely contents of specific individual booster packs.
Box mapping is the practice of finding these large-scale patterns within booster boxes and using that knowledge to cherry-pick the individual booster packs with the greatest likelihood of containing the most valuable cards in the set. Those packs are opened and the valuable cards sold off for a much higher price than the packs themselves would have netted, and the remaining dross packs are sold at regular price to those who don't realize that they almost certainly contain no rares of significant value.
Yes, it works. It works because Wizards cannot realistically make booster pack contents truly random, nor do they even want to, really, and thus, no matter how complex the pattern, there is a pattern. Wizards changes up the system whenever they discover someone's cracked it, but there's always going to be a pattern. And if there's a pattern, someone can find it and exploit it.
Qui va più nel dettaglio:
http://forums.mtgsalvation.com/showthread.php?t=482863
(no dico sul serio, tutto questo rende solo il prodotto sigillato insensato, ma è il trend su cui naviga il gioco ultimamente).
