HC, if you can wait till after the 23rd I'll e-mail you the relevant pages from the RFM (in the UK now so don't have it to hand).
I think the question you raise has some merit but equally has a pretty obvious answer; attempt to fly out of icing conditions! I wonder whether fixed wing a/c have specific advice for similar situations? Somehow I doubt it.
I guess other analogies include flying above Vne for flotation gear inflated or power off: Do you limit your speed on the off chance the floats inflate inadvertently or you have a double engine failure?
Best to fly somewhere with no icing!
