A British aerial photographer was arrested while flying his drone by authorities, even though he had authorization from the CAA (the British equivalent of the FAA).
He was attempted to obtain pictures of a fire and had verbal authorization from the landowner. The police arrested him for “breach of the peace” and took the controller away from him to land the UAV themselves, but released him without charges 5 hours later. He has not received his equipment back as of yet.
He filed a complaint with the CAA regarding the incident and I will follow this story.
I also saw a post on a legal UAV blog about a recreational user in the US who was visited by police after neighbors complained about the use of a UAV on his property.
UAVs garner strong opinions, and police (and your neighbors) can still make trouble, even if you are complying with the FAA guidelines. Be ready to justify your actions!