On the subject of you-tube or similar videos in general:

I think SOME you-tube videos are completely misleading, especially if you are directed onto an American or international video, and you try to learn from that information without knowing its completely wrong. 

I think SOME British aimed you tube videos are very well meaning and well intended, and show one way to do the job

I think some British aimed you-tube videos are very good, but out of date; 16th, 17th, 18th edition information or whatever the case might be.

I think SOME British you-tube videos are very well meaning and partially wrong

I think some British you-tube videos are simply brilliant (eg sparkyninja and John Ward)

I know though, that when I don't know how to do something - one of my first places to look is you tube.

Usually for things - in my case - outside normal electrical stuff, such as my dishwasher condense pump wont turn off, why, and how do I change it? Or my VW window won't wind down, why, and how do I change the window winding motor.

I assume most people are the same for electrical tutorials. 

So no, not at all, "dangerous to all" - but potentially, yes the information may be right, wrong, partially right, partially wrong or very good. Unfortunately it takes experience to decide what information to listen to. 

On the subject of you-tube or similar videos in general:

I think SOME you-tube videos are completely misleading, especially if you are directed onto an American or international video, and you try to learn from that information without knowing its completely wrong. 

I think SOME British aimed you tube videos are very well meaning and well intended, and show one way to do the job

I think some British aimed you-tube videos are very good, but out of date; 16th, 17th, 18th edition information or whatever the case might be.

I think SOME British you-tube videos are very well meaning and partially wrong

I think some British you-tube videos are simply brilliant (eg sparkyninja and John Ward)

I know though, that when I don't know how to do something - one of my first places to look is you tube.

Usually for things - in my case - outside normal electrical stuff, such as my dishwasher condense pump wont turn off, why, and how do I change it? Or my VW window won't wind down, why, and how do I change the window winding motor.

I assume most people are the same for electrical tutorials. 

So no, not at all, "dangerous to all" - but potentially, yes the information may be right, wrong, partially right, partially wrong or very good. Unfortunately it takes experience to decide what information to listen to. 

Very true- and before the internet it might have been a friend of a mate at the pub who advised on how to fix the car or whatever - the problem really is in a lack of selectivity - how much trust do you place in someone you do not know anything about.
The internet mentality is that folk with a flashier style get more views and to the top of the search algorithms, - again this is not the same as being technically 'right'.
Mind you, the same caveat should be raised for this forum too - the advice may be wrong, not perhaps t because the poster's knowledge is incomplete (though it may be),  but the question asked may also not present an accurate picture, and the missing detail may have changed everything.

I'd not be in favour of banning/censorship, but a general education of the viewer to the variable quality is important.
Mike.

Disclaimer.
The author's ideas are his own and not his employers, and may or may not add any value to the discussion. Advice given  may be incorrect or incomplete. The voltage  of the electrons you put in may go down as well as up.etc etc.