See various questions about CRT replacement, where the original poster shows neither awareness or unawareness of the hazards involved.
Should it be assumed everyone will be safe by virtue of their own diligence, so one should be friendly and not warn sternly - or should the assumption always be that whoever doesn't reasonably prove they know how to be safe does not?
I would not want to assume that a stranger is aware of how to handle high-voltage circuits.
A key feature of Stack Exchange is that the Q-and-A's are intended to be kept available for the benefit of future readers. Even if the original poster shows awareness of the hazards, one cannot know whether others who search for the same question will know what precautions to take. As they're not writing the question, they have no opportunity to show us if they're unaware of the dangers involved.
My preference would be to put a brief disclaimer prior to any answer that I write about repairing such items, noting that care is needed when dealing with high voltage equipment. This can be done in a friendly manner, but there should be a warning. (I don't feel there's a need to list all the precautions every time, just inform or remind readers that there are added dangers involved.)
If the original poster has acknowledged the hazards involved in the question, or the question is of such an intricate nature that it goes far beyond opening the box and looking inside, then that may be sufficient warning for future readers.
(This reflects the common practice on a number of retrocomputing-oriented web forums that I frequent.)
I think we should try to minimise our site's casualty rate. Scary bold warnings at the top of answers, and just before dangerous parts of how-tos is within our ability, so I think we'd be stupid not to use them.
Modern people probably aren't used to televisions and monitors being deadly weapons of deathly death.
