Every flipped face, every flipped R2, every major flipped asymmetrical object sticks out like a sore thumb and takes the viewer out of the moment, especially in the modern age of repeat viewing on DVD etc.
Doing it creates so much visual jarring that anything that was hoped to be gained by doing it in first place is lost.
Maybe it's just me, but those things don't jump out at me. I'm a big Star Wars fan, but I almost pride myself on not actually knowing which way around the tubey thing and the flashy thing go on Artoo's head.
Would you flip this if it was the wrong way around? (e.g. if Sam had the strap over the other shoulder, or Frodo had a restraining bolt on the wrong arm)

DE