The cottage can accommodate 2 guests, as well as a third and fourth person in the living area at an additional cost, and for a maximum stay of 2 nights. (travelground.com)
If you're only the third or fourth person on the email chain, then you have an obligation to acknowledge that you have been pulled into the conversation. (entrepreneur.com)
Kids don't pay less, but there are third and fourth person rates. (bostonmamas.com)