As a member of the Institution of Engineering and Technology I get the excellent E&T magazine to read.  In this months edition there is a balanced  article  about agricultural use of RPAS (Remotely Piloted Aviation System) or drones.   It points out the unresolved legal and safety issues relating to this technology.  It is great fun to play with the technology but does it bring any financial benefit?  The use case they highlight is a vineyard in California and it is the very high value crops such as fruit that are the most likely places where this high cost technology adds benefit.