Not only do modern kimono warriors shun white undercollars & sox, they sometimes even layer on frilly Western pieces to add a little spice.
New 'Kimono Hime' style of wearing kimono
And Kimono Princesses sometimes wear jewelry. (There's actually a reason Japanese women don't have a big history of wearing rings, necklaces and pins – kimono fabrics were often more costly than jewels, and nobody wanted to risk something snagging or AI YI YI putting a hole in the priceless fabrics. But new style kimonos aren't expensive – most of them are vintage – so even cheap costume jewelry is safe to wear.)