The ways in which people get paid for making music are many and various. One is royalties generated by live performances.
A typical scenario would be that you, or your band, play live at a gig that is of a size and status sufficient to be tracked by the society that collects performance royalties for the country in which the gig takes place. Or someone else could cover one of your songs.
Data from these 'significant' performances are collected and used to share licence fees paid by all performance venues, which in most developed countries have to pay a music performance licence fee by law. Obviously, it is impossible to account for every song played everywhere so only a certain number of venues can have their data fully tracked and analyzed.
However, there has suddenly emerged a loophole in Germany where support acts could find that they are not paid properly for major concerts and tours.
What happens is this… The main act receives all of the royalties for a major tour and the supporting act receives none from the tour directly. The supporting act would still receive royalties through the normal mechanism outlined above, but this does not account for the size of the audience for the tour. So the main act gets everything and the supporting act gets peanuts.
Of course if you are a supporting act, maybe that's all you would expect anyway. Official advice is that the support act should agree a division of royalties with the main act. But as support acts often have to pay just to get on the stage in the first place, this isn't really likely to happen.
Despite the efforts of the collection societies to ensure fair distributionof revenue, it's still dog eat dog in the real world of the music business.