Opinion = I think the water temperature was too hot to be safe for children.
Fact = The water temperature was 140 degrees, and capable of burning a child within 6 seconds of exposure.
I'm not saying that we should go around with thermometers in our pockets, but you can't say for a fact that the water was hot enough to burn a child without one. That's why it was opinion and not fact.
A quick search shows that pediatricians suggest setting water heaters at 120 degrees, which would take several minutes to burn a child with repeated exposure, BTW
It may be plainly obvious that the water was too hot and the client could be possibly in danger of a lawsuit for not taking child safety into account, but that wasn't the question asked. You need to accurately gauge the temperature before making a comment like that if opinion is not allowed in the report.