Thanks Guys for all the advice.
Had confirmation of your thoughts from Canon. I was actually trying to get some info about the 40mm f2.8 and realised I was talking to one of the most knowledgeable tech support guys - so asked.
He also confirmed can't damage camera, or lens. He said he does it all the time and has for years!
Ref the IS being in operation, he said what would damage it was if you gave the lens a big physical sharp shock i.e. dropping it when the IS was going - that is, as I'm sure everyone realises naturally going to be bad news; but he confirmed especially for the IS system.
So thats doubly reassuring.
