I think that's hilarious! Outrageous, but very very funny as well in a hideous kind of way. Snobby schools don't usually let the mask slip quite that badly.
Though we were visiting my dc's cousin at her smart boarding school when dd1 was in about Y5, and cousin's housemistress asked where dd1 went to school. Dd1 brightly answered: "Hackney.". I wish I could have bottled the look the housemistress gave her, it was priceless.
Their loss.