Here's what would be great: 1. Person A takes the initiative and books an Airbnb 2. Airbnb gives him a link to a landing page. 3. On this page, his friends c

Here's what would be great: 1. Person A takes the initiative and books an Airbnb 2. Airbnb gives him a link to a landing page. 3. On this page, his friends can 'opt-in' to the vacation. When they opt-in, the cost gets split. Say, if the rent/night is $200 and 3 people opt-in, the cost would be $50 each (including person A). 4. Each person who opts in gets charged for his share. 5. Airbnb can also promote other services on this custom landing page such as guided tours. Person A doesn't have to worry about getting the 'yes' from his friends; if you've opted in, you're coming.