If, when designing a retail environment, you could a) increase sales and b) make customers feel better about themselves by using a ’slimming’ mirror, why wouldn’t you? How ethical is this? It’s an underhand method of persuasion rather than physical control, but it could make a significant difference to sales, in the process making shoppers feel more positive, even if ultimately it’s deceitful. Hewlett-Packard already produces digital cameras with a ’slimming’ mode. If it helps you modify your self-image, and you like that, then I’m not sure it’s unethical per se. It’s just part of the great embedded architecture of delusion that fuels modern consumerism. Vanity sizing - another method of persuasion in clothes retailing - is an additional aspect of this.Link
Mirrors are a useful persuasion and control tool for retail designers anyway, whether distorting or not. People stop or slow down when they encounter them. Sometimes it’s vanity; sometimes it’s simply useful for people to see how they look.
I write books. My latest is a YA science fiction novel called Homeland (it's the sequel to Little Brother). More books: Rapture of the Nerds (a novel, with Charlie Stross); With a Little Help (short stories); and The Great Big Beautiful Tomorrow (novella and nonfic). I speak all over the place and I tweet and tumble, too.