Yeah but you are talking about hot tubs and they are talking about hot tubes so maybe the rules are different like the tube is really hot but is a poor thermal conductor. Or they misspelled tub and they really like burning themselves...... lots of options for interpretation here.
It could also be a gross sex term for a dick. During sexy time someone could say to me "yeah give me that hot tube" and I would be immediately less interested in sex.
Most adults will suffer third-degree burns if
exposed to 150 degree water for two seconds.
Burns will also occur with a six-second
exposure to 140 degree water or with a thirty
second exposure to 130 degree water. Even if
the temperature is 120 degrees, a five minute
exposure could result in third-degree burns.
To be honest three degrees burn doesn't sound bad. I'm looking at my protractor and as long as you aren't far away from the tub three degrees shouldn't burn that much