I came across this post where somebody want to drive a string of LEDs from mains power.
Only one person ( Colin__s ) had a small note of 'Use a power supply'. Then nothing for ten hours. I just came across it and posted an answer with big DON'T but it had been up for ten hours before that. (And closed about five minutes after my post)
I found this link about 'What is our policy on dangerous stuff?' which only says: "I don't think that we should have restrictions on electronics which are perceived to be dangerous."
But should we have a policy of pointing out, clearly and with emphasis, when things are dangerous?