Yes Dave the Gnome. Though it is seldom a problem, as the Internet is so vast. But you can have any copyright material pulled, whether money is changing hands or not. Also even youtube have started placing adverts on channels. The big guns use auto recognition software to pick up on song use, but it is seldom effective and often wrong. As in the case of Albert Lee and Vince Gill. It only picked out two songs, and not the actual recordings being used. So it will not at the moment pick up on Joe Bloggs performing a cover of some obscure folk song. The copyright notice you receive is not permission, it just means that two songs were picked up on, and that the owner can place adverts on the songs, usually instead of having them removed. But they can still ask for removal. All rights holders can have anything removed, but many are happy to see old recordings appear. But as said, the artist may not have the right to give permission on the song they are singing, unless it is truly traditional or they own their own rights.