You are right Stuart, this the main reason why a tub in Canada is less likely to freeze. The tub isn't quite sure what temperature is correct.......unless its a D-1 displaying in Celcius.
That is one feature, that I wish we had. I am a Celcius guy through and through...except when discussing hot tubs! I highly doubt many of my customers would share my opinion though. Most are dedicated Fahrenheit fans.
Maybe we should all just agree to use Kelvin
On the plus side we would never have to put in a degree symbol anymore.