They have spent decades dumbing down the average American, I think the warning as valid, only while operating adds a level of notification that would require another sign indicating the heaters are in operation ..... possibly a detailed explanation of what "operating" meant in this context .... and all this relies on the person or persons being able to read the language the sign is written in.......
Lessons learnt from the Workplace Training and Assessment Cert 4 certification I attained many moons ago, employ the "KISS" principle to all instructions
Although, we would have received extra marks if the radiated heat wavy lines were red and smoke was drifting up from the hand and fingers ....... The classic "Do Not Touch Hot" sign got the usual ridicule:
Can they read?
Why is the sign hot?
Invites the "Wet Paint" test
and a heap more that I can't remember
The picture type sign, even DJT could identify ...... it doesn't matter if the heating is operating or not, don't touch or you may get burnt and you were clearly warned is the message the sign portrays ..... if you are stupid enough to touch this area and you do get burnt, there is no compensation for stupidity
T1 Terry