As we've said all along in this thread, it very much depends on your own viewpoint. Personally I doubt very much I'd ride into someone's mirror unless I was forced into it. We all ride fairly defensively on bikes because we're vulnerable. If by chance I did ride into someone's mirror and totalled it, I'd pay for it, I don't need insurance for that. In exactly the same way if in life I did something which damaged something, I'd pay for it, I don't think the risk is any greater on a pushbike, except to me.