I too have run into the same problem. In my case, because, I work for a non-profit (and am tax-exempt), items get "returned" by staff so that they can adjust the sales tax.
As per the advice given to me by a manager at Best Buy the solution to this is to create a new Best Buy account profile (as the return activity is tracked via email). I suppose using a different credit card could help.
Given that a work-around is trivial, it seems this system just serves to frustrate customers.