I think mickjoebill was looking for a CUBE (50x50x50ft) not if a pilot can maintain a high hover at 1500-2000 ft. within 50ft. tolerance.
When you get to that sort of altitude, you can sit in what you think is a perfect hover (maintaining altitude) but still drift for/aft, sideways those feet without you notice it, and be well outside of the 50ft lat.long before you adjust for it. Your periferal references at such height is just not sufficient.