I'm sure it was an accident- it's very difficult to guage depth perception when flying a plane at any distance; he probably thought his plane was well on this side of the wires.
On a related note, I've got a little R/C plane I fly all the time in this tiny little park beside by house that not only is too narrow and too short to really be flying a plane in, but ALSO has high voltage lines running about 50' up! Needless to say, I have an interesting time- I can't tell you how many times I've bounced off those lines. (The two planes I fly there only have 2' foam wings and are way too small to short the phases.) The lines dent the styrofoam when it impacts, though. Usually, it recovers before it hits the ground, but is porpoising so badly I have to land anyhow.
Edit: he probably had metal aileron pushrods in that- I can't see balsa or foam alone being a good enough conductor to explode like that!
[This message has been edited by SteveFehr (edited 06-16-2006).]