"The FAA has released a set of cease and desist letters sent in 2012 and 2013 to people operating drone vehicles for a variety of purposes including: tornado research, inspecting gas well stacks, aerial photography, journalism education, and other purposes. Drone cease and desist letters sent during 2014 are available from the FAA upon request." The text of the letters (bureaucratically polite, but bureaucratically firm) often starts with notes indicating that the UAV operators to whom they were sent that the FAA became interested in them because it "became aware of" their web sites, or even because someone tipped them off about an article in a community newsletter. The letters go on to outline the conditions under which the FAA allows the operation of unmanned aircraft, and specifically notes: Those who use UAS only for recreational enjoyment, operate in accordance with Advisory arcular 91-57. This generally applies to operations in remotely populated areas away from airports, persons and buildings, below 400 feet Above Ground Level, and within visual line of sight. On February 6, 2007 the FAA published UAS guidance in the Federal Register, 14 CPR Part 91 / Docket No. FAA-2006-25714 I Unmanned Airaaft Operations in the National Airspace System. Toward the end of the docket it says, ''The FAA recognizes that people and companies other than modelers might be flying UAS with the mistaken understanding that they are legally operating under the authority of AC 91-57. AC 91-57 only applies to modelers, and thus specifically excludes Its use by pecions or companies for business purposes."