ORIGINAL: B.L.E.
Most full scale airplanes land with flaps down. These flaps, in addition to providing a lower stall speed and extra drag so that the plane can have a steeper glide slope, also effectively give the wing tips washout when employed. The ability to reflex barndoor style ailerons up also acts as temporary washout, allowing a surprise free landing. Tip stalls are deadly when the plane is low and slow, i.e. during a landing approach.
I agree with all of that. Except that I would tongue-in-cheek add the condition that
unintentional tip-stalls can be deadly. Low level snap rolls are cool, and relatively safe when done by an expert aerobatic pilot at an airshow or contest.
I lost count long ago of all the models I have seen lost to unintentional tip-stalls/partial snaps/incipient spins. Almost always, the pilot does not fully understand stalls, and especially what causes tip-stalls. It's amazing how much difference a correct understanding of aerodynamics can have. Often the difference between crash and no crash. Every now and then a gentleman will set himself apart by freely admitting that he just plain screwed up, instead of trying to blame it on the radio, or the design of the airplane, etc.
Here's a scary story: I met a guy who stalled/spun/crashed a KR-2 and lived to tell about it. He was maimed pretty badly by the accident. It was clear to me from his description of the accident that he didn't understand spin recovery very well; "I kept moving the controls around but it wouldn't recover". Now for the really scary part: The one and only time I met the guy, he was building another KR to replace the one he had crashed. He hadn't gone back and studied and did not seem to have learned a thing from his accident. He didn't seem to know anything about emergency spin recovery, or the contribution that rudder coordination (or un-coordination) makes to spin entry. I don't know what ever happened to him; it was many years ago.