This would be about as useful as telling the cat why he can’t go out right now. The words would not be understood, as they won’t be by probably 90% of humanity.
> If they want to…
They don’t. Categorically. The only reason they would try is because they are being scammed with offers of getting something or cajolement entreating them to allow it.
> Why should you have control what they can or cannot do?
Me? I’m not asking for control. I’m saying that most people aren’t equipped to understand the threats they face, even in the face of explanation or warning, and their use-cases are comprehensively covered without it. My parents are old. My brother ends up with any PC he owns full of malware and viruses. The current status quo serves them and many millions of other people very well, and we need to be very cautious when arguing to rip this away in the name of our freedom - to them it only represents freedom to be exploited.
> Should experts in other fields also be able to control over what their layman family member…
Experts in other fields determine the extent of what all laypeople may do legally all the time. Or do you live somewhere that there are zero restrictions on (for example) gas plumbing or work on electrical systems?