As a pilot, just as I wouldn't be in any hurry to fly in any aircraft designed and built in a hurry, I also wouldn't want to be on the ground or in the air anywhere near something airborne built by people who aren't familiar with airspace regulations, not to mention the physics of flight. This is especially true in an environment where relief and search and rescue aircraft are operating - there is way too much that can go wrong just with their operations, and tossing this kind of wild card into the mix is highly inadvisable. There's a very good reason why we spend as much as we do on military, law enforcement, and search-and-rescue professionals and equipment.
The Arduplane software is, at best, only suitable for use in toys. There is nothing in it to ensure reliability of flight, and the entire flight system completely lacks any redundancy or graceful degradation when, not if, failures occur in hardware and/or software. Plus, there is nothing on-board to aid in collision avoidance, which is the number one risk in scenarios such as disaster relief. The sky is an even less forgiving mistress than the sea - and both routinely teach even the best professionals hard lessons every day of the year (see also Captain Sullenberger's comments on this subject).
Now, if they were to do simulations on the Pi using its wonderful GPU, I would fly and rest a whole lot more easily!
The best things in life aren't things ... but, a Pi comes pretty darned close!
"Education is not the filling of a pail, but the lighting of a fire." -- W.B. Yeats
In theory, theory & practice are the same - in practice, they aren't!!!