I wouldn't buy that argument that this does anything to harm the customer.

I still don't buy their argument about savings.

People will buy anything that is 'one to a customer.'

There is never a good sale for Neiman-Marcus unless it's a good buy for the customer.

I don't buy [the currency] argument. I was expecting more. That jumps right out.

The person would get embarrassed, and feel like you were calling them out. You'd have to verbally win the argument, or else just get the bouncers to escort them out.