It doesn't look to me like they do much checking into who actually created or has the rights to any particular model.  They just broker the sales.

So, whoever sent the pilfered models in to them is primarily at fault (and is getting most of the ill gotten gains from the sale).

However, if ES is going to put itself in the position of brokering sales, they should, at a minimum, get proof that the seller has good title to what they are selling ... or they are going to get burned.

Could be worse, could be raining.