This very subject came up on More Or Less (BBC Radio 4), where their metier is to be as pedantic about the public use of statistics as we are about language.
There was a flurry of responses from the "loyal listeners" when a statement (in a public safety / life saving context) said something like the sea temperature at 9 degrees is a third the temperature of a swimming pool at 30 degrees (I may not have remembered the details exactly), resulting in a much greater risk of hypothermia/exposure if you find yourself immersed in it.
The arguments were as above, but Tim Hartford defended the original speaker as not having a scientific background (therefore no knowledge of thermodynamics), and it was in accord with public perception. I subsequently wrote in saying that the rate of heat loss from a body is proportional to the temperature difference to the environment and the specific heat capacity of the environmental medium - so it would make sense (in this context) to take body temperature as the datum (37 degrees), and thus the chill effect of being immersed in the sea is nearly four times greater than in a heated pool.
Thermodynamically, MET is correct - but what matters in any such case of comparing number is the magnitude of the practical effect.