Commercial: Selling mistakes

Howies' tone of voice is generally on the money. I thought this example from a few weeks ago was very clever indeed.

Not only did it position 'mistake' t-shirts as a desirable item, it also had a good crack at persuading you to pay more for them than their normal t-shirts of the week. That's very canny indeed. I'd love to know how successful that approach was - the anti-sale, as it were.