Nice Cheeky comments above. Certainly a reversal of the traditional HOUSESITTING model, eh?
Even most HOTELS don't charge a different room rate for two people vs. one. That is a very distrubing and newly noticed "trend" to charge based upon the number of occupants. It's BS gouging. Set a damn price and stick to it without games....
I think it's equally in line with PT Barnum's "sucker born every minute" approach.