I have heard that Chicago, Kansas City and Buffalo are NFL stadiums that do not have underground heating systems. Is this correct and if so why are they making such a big deal out of the fact that they have to play one game at TCF stadium in Minnesota tonight where the Gophers have no unerground heating system. I realize it is colder in Minny sometimes but 19 degrees tonight is very similar to or even a higher temp than Chicago has on many dates in December.