Took an urn through TSA in 2013. I was ready for an ordeal, but TSA did not require that the urn go through the x-ray machine and simply swabbed the outside for explosives. In my case they did not need to open the urn. YMMV, but TSA was very respectful and explained exactly what and why they did everything.

Also, no issues with DL as I just put it back inside my carryon bag. I feel that checking the remains may cause more issues with your luggage being searched in a more reckless manner.