According to Abba: The Official Photo Book, published to mark 40 years since they won Eurovision with Waterloo, the band’s style was influenced in part by laws that allowed the cost of outfits to be deducted against tax – so long as the costumes were so outrageous they could not possibly be worn on the street.
I’ve read the comment, but that’s not how taxes usually work. (It is, however, like a lot of people with little knowledge about the topic think tax deductions in general work - which makes me suspicious)
It would take bit more of the than that comment at face value to convince me that apparent law exist(ed)