...you answered my original question. I was 
wondering how AL expected to catalogue everything 
in such a way, but if it's whether things have 
passed through their hands at all, I suppose I 
understand. Of course, then it comes down to the 
exact science of sequences numbers, which aren't 
always provided...

Although, I do think it's a bit rash to stop 
people from trading cels just because they never 
passed through AL's hands ^^;; There's going to 
be some cel theivery, and if a cel that was 
stolen somehow ends up in, say, my hands, and I 
want to sell it, will AL stop me just because of 
the original source (which I might not even have 
a clue of)?

-Misha