Buttocknurdler,
Thanks. So it turns out to be the same reason as the Bell 47 after all.
I suppose I shoulda guessed, but I didn't want to answer my companion's question with guesswork.
With the Hughes's tail rotor being on the left I couldn't see any safety advantage to sitting on the left when so close to the lines.
Interesting prog all the same -- and maximum respect to those who fly such work routinely. Superb accuracy of flying and tremendous stamina. Lovely teamwork too.