We can be fairly certain of nothing, considering 1) you have no idea who opened those coins, and 2) no smart thief would load none. I'd be happy to skim 1 of every 100 1BTC coins sold, for an extra $383 dollars.
In that case, why don't I just raise my price 1%? The market will already clearly bear it.
Yes, yes. There's all kinds of legal avenues we can take advantage of to get back our stolen BTCs from you. 
The fact is, anyone stupid enough to trust you like they trust their grocery store probably deserves to lose everything.
The fact is, anyone stupid enough to trust you like they trust their grocery store probably deserves to lose everything.There actually are legal avenues, no different than if I claimed to sell designer handbags but shipped knockoffs. Now, it would actually be a joke - as you suggest - if I owned no significant assets to go after, but that's not the case here. If a lot of people believed I were stealing their coins, they would probably have no problem finding a lawyer to pursue the case on contingency.