I don't. In the era that this device would have been found in use, both adults and kids had more common sense and maturity.
I agree entirely. If it were being marketed to 6-year-olds to play with alone, then there might be cause for concern, and a harmless battery-powered version would be far more appropriate. But items such as this (and the resonance demonstrator in the other thread) were clearly designed and build for class demonstrations where there would have been suitable supervision.
It seems to me that these would have been set up on a bench and the class gathered round to watch the demonstration. In fact we did just such experiments when I was in school in the 1970s, both physics and chemistry.
If we're going to insist that the equipment is completely covered and idiot-proof, then we'd better not let chemistry students handle bottles of hydrochloric acid. Better not let the girls handle hot cake trays in cookery classes either (if they even
do cookery these days!).