Sensors do not "charge" with static when running.
Its one of those internet "facts" that gets repeated, until it becomes "truth".
I'd agree you should turn it off, but not for the "static" myth.
Another urban 'fact' exposed eh
So why turn it off then?
DD
2, the lens and body contacts are live. Disconnecting and reconnecting live contacts could cause a power surge / arcing and could potentially damage delicate components.
I thought it was the 'norm' to turn the camera off
Do you turn off your camera before changing the lens? I always do these days after my 350 crashed when I forgot to turn it off and changed lenses. Had to pop the battery out to reset it. Was a scary moment.
^True
As you rotate the lens into the mount all the lens contacts connect to the body contacts in the wrong order until it is seated correctly.
Doesn't take much thought to realise this is potentially a bad idea when the body is live.
I think you'll find that that scenario is safely catered for by having the power contact being the end one and is not in contact until the final part of the rotation.
Bob
I read a response from Canon's North American CEO (Chuck Westfall) to a question and answer session last year where he stated that it wasn't neccessary to power down the body. I'm pretty sure that the power switch doesn't remove power from the lens contacts anyway.
Bob