Although these may well be a thing of the past after a Korean scientist discovered that the neutral temperature for surface contact with your arse is 32.6 centigrade (i.e. the temperature at which a surface feels neither cold or warm).
He discovered this by using a bunch of students and some underfloor heating (hmm, nice work if you can get it).
No doubt we will see the introduction of thermostatically controlled bog seats in the near future.
Madyakker 
