You're correct in that as far as I know. Unless 
someone turns you in, they don't send notices 
like that. It's just like the problem with 
doujins, and what happened with Parrallax. 
Someone takes offense to the wording in a 
description, or a scan of the cel/part of the 
doujin and thinks it's too "revealing" so ebay 
will either move it to an adult section or just 
close it all together (the second is the most 
likely). :P   It basically boils down to people 
who have too little to do with their time looking 
for people to mess with.

In an off-topic example, I had placed an item 
into a category that was as close as I could come 
to what I was selling. It was a Hartland model 
horse and I placed it into the Breyer 
collectibles category. Someone complained and my 
auction was closed :P  *rolls her eyes*  

Anyway.. just my random thoughts and 
experiences. :)
Sheri