Helicopter   

 good neighbor has nothing to do with cow-towing to another.  Being reasonable is the way to behave, for both parties, but telling a neighbor they have to restrict the use of their back yard to suit some exclusive concept of 'conditional cancelling of one's neighbor's freedom of use of personal property' is selfish, childish, and unethical with no reasonable basis in any sense.  You know, millennial derangement syndrome.  How their parents ever raised children with such an arrogant nature is negligent at best.