Some fakebooks, sheet music and other songbooks often use ALL CAPITAL LETTERS wherever the title appears in the lyrics, e.g.,

Oh, my darling, oh, my darling,
Oh, my darling CLEMENTINE
You are lost and gone forever,
Dreadful sorry CLEMENTINE

This can look truly ridiculous, especially when the title appears frequently.

Is this some strange custom, a copyright thingamabob, or what?