TFR based on an invisible VOR?
After I brought this to the attention of the local offices, they canceled the TFR and issued a new one expressed in terms of the MCI VOR, which makes a lot more sense. The FAA was incredibly responsive and helpful!

They didn't explicitly say it was a mistake, but I think they decided it was better to use an operational VOR.

(however, a couple weeks later, they referenced the RIS VOR again in a NOTAM.)