Sorry, I have to agree with the majority here, although I'm not going to abuse you about it. If you are returning well over half the shoes you buy, and you have run at least a few miles in them, I think it makes sense from the store's point of view to decide it doesn't want you as a customer, or at least that it isn't going to allow you to return any more shoes. I think this would be true regardless of your race.
I have never returned shoes to a brick-and-mortar store. I sometimes return shoes I buy online, but only if they are obviously wrong the first time I put them on. I've never returned shoes after running more than a few tens of meters in them. And as others have said, I would not want to buy a pair of "new" shoes that someone else had already run 10 (or 5) miles in.