Unethical - No. The smartest thing you could do, No on that one as well.

I have a feeling you're not talking about driving rain and 25mph winds as I think most of us are smart enough to get down from a tree by that time anyway. During light rain there should be no problem if you limit yourself to good broadside/quartering away shots from a reasonable distance. Many times I've sat in the cabin waiting for the "hard stuff", to quote Bill Murray, to come to an end to get back in a stand while there's still a little rain falling.