An even more outrageous instance I discovered recently was a contemporary Christian CD that was older songs, pretty much all from 20th C. hymnals, done "in comtemporary style."
So far, so good.   But the liner notes and CD label had every last one of these songs listed as "traditional!"
The names of the composers and lyricists for all of those songs are not only known, but all you have to do to find the proper credits is open a standard hymnal, for crying out loud!   Or you can go to cyberhymnal.org or (in many cases) check Wikipedia.   It's not like any of these songs (e.g., How Great Thou Art;* In The Garden; Nearer, My God, To Thee, ) are associated in the public's mind so strongly with any recording artist that the performer name replaces the composers'.   And it's not like calling them "trad" prevents having to pay royalties, either; they were pretty much all in the Public Domain by now. But PD doesn't mean "of anonymous authorship."

*Yes, in some cases the melodies actually are "traditional." But even then, it's better to say "Swedish folk melody," for example, than just "trad" -- which may be taken to mean no one has a clue as to where it came from.