When you tube recieves a complaint from anyone wo holds a copyright theythen check to see if there is a case, doesnt matter if money is being made or not. 

I have a few thousand followers on tik tok and they scan for copyright infringement as soon as you upload a video, if you infringe copy right they will not let you upload, most copyright hits especially for Irish or old tunes revolve around similarity to other artists work, and their ability to prove that they are the sole rights owners and that they are the original content creators, this is very difficult to do with folk and other tunes which were written in the dim past, and rules are also different in other countries, consequently especially on you tube the hit fails, and the video is left alone, but with the statement copyright infringement left on the video to show it has been challenged, these days I just delete the video and re upload as they then cant place their copyright statement as its already been challenged.

Thanks for your comment Sasha, much appreciated.

Mouse, quite correct copyright law is very complicated, in the Uk most things over a certain age are public domain, such as Irish tunes and old English folk stuff, as I mentioned, but if a tune is significantly altered the person changing it can try to gain copyright, (usually fails), I still have one on you tube with the copyright notice attached, and the tune was actually originally written 400 years ago. I was told the baroque group who had a version were not bothered, cant see how they could have done anything anyway though. 

A lot of modern artists are quite hqppy,for other people to play their tunes on platforms such as you tube (as long as they are not making money) as it promotes their tunes.

But I agree that stealing stuff, just isnt on.