[Espy]

Delivered items don't go into the backyard in the first place, so pools won't be a problem. Drones are most likely going to just leave your package near your front door, regardless of your presence at home.

And people exiting their door -- I assume you mean that it'd be a collision hazard. Have you seen Google's self-driving car prototypes? Similar technology and programming will be used for the drones, probably, so the drone would be equipped with at least a couple cameras. Avoiding obstacles, making sharp turns, adjusting to wind speeds, etc is a piece of cake.

If the addresses are wrong...hm. I'm not sure how this would happen, if the consumer entered the correct address while making the purchase. The drones would likely be using stuff like Google Maps or a similar Amazon version, so there's very little chance for there to be an address error on the drone's side.

Also, I see you've made the assumption that only wealthy people would have access to this type of service. I don't understand why you imagine that would be the case; care to elaborate?