I'm thinking that big box electronics stores in urban locations are generally just under a lot more pressure. Their customer base has less expendable income than a suburban crowd, the threat of theft and general dishonesty is lower than in the 'burbs, and the people they deal with tend to be pushier, more demanding and less patient. Therefore, they're more on guard when it comes to sidestepping customer demands and shutting down bogus requests, so they have a much better knowledge of things like official store policies. Or maybe it's just pure luck.