As I always use my two 600s off camera, with STE3 trigger in radio mode I bought a couple of cold Hotshoe umbrella Holders.
Probably not the right description, but they are metal, fit on a lighting stand and have a clamp for an umbrella.
Then I thought when they are triggered - could the electrical pins on the base of the 600s short on these metal brackets?
Should I tape the inside of the bracket with electrical tape.
I am assuming they will not as the little accessory feet are metal, but just thought I would ask.
Its difficult to see e if they touch due to the weather sealing lip.
Any views welcome. I asked Canon UK who said " uhmmmm interesting point - see your concern - but I don't know - I will check," but they have not got back to me.