I think the "dorks" in the photo wear them that way to display the bib part, so you know what you are buying. If the model had a jersey over them, like 99.9% of the bikers wear them like, you wouldn't be able to see the bib part.

I wonder how many fancy bike poseurs see pictures like that when buying their Assos and wear them the same way because they don't know any better? I'll have to keep an eye out at the coffee shops.

This should be added to the OCP list, wearing your expensive bib shorts OVER your expensive jersey because that's in the catalog pictures.