Okay, I have to chime in. I thought this thread was going nowhere. But
Yes, I do sometimes wear jeans under my leathers. Not "race leathers", by the way, just a good set of touring leathers.
I have a few friends that live on the Peninsula. When I visit them (usually taking the "scenic route" down Skyline, "the" 84, "the" 9, etc), I often don't have room in my tankbag for my street shoes, water, etc., etc.,
and my jeans as well. So yeah, I wear them. They are a little tight under the leather pants, but it's not like I can't operate a vehicle or anything. Most cold-weather gear is at least as constricting. Hey! I've even been known to put a sweatshirt under my jacket when it's cold
So don't be put off. It's not like you will die if you wear jeans under your leathers. Unless you are riding a 600. And you have only been riding for six months or less. Then you will die for sure. Unless you get a SV650 or a 250 Ninja. Or a Busa.