From the New York Times:
Mr. Waits has won wide acclaim and a cult following for his ballads of gutter characters and doomed lovers, sung in a distinctive sandpaper baritone. But that style has attracted imitators over the years, particularly in the advertising world, and Mr. Waits has established a laborious side business protecting his musical identity.
Sixteen years ago he won an influential case against Frito-Lay over a vocal sound-alike in a Doritos commercial, and he has pursued imitators ever since. Last Friday Mr. Waits was awarded damages in a case against the Audi division of Volkswagen for a commercial in Spain using music that was similar to his song "Innocent When You Dream," sung in a voice like his. Another lawsuit is pending in Germany against the Opel division of General Motors, this one for a version of the Brahms "Lullaby" performed in what he calls a suspiciously Waitsian voice.
"It does take a tremendous amount of time, energy and money" to pursue these cases, Mr. Waits said from his home in Northern California. "But in a way," he added, "you're building a road that other people will drive on. I have a moral right to my voice. It's like property - there's a fence around it, in a way."
..."It's part of an artist's odyssey," he said, "discovering your own voice and struggling to find the combination of qualities that makes you unique. It's kind of like your face, your identity. Now I've got these unscrupulous doppelgängers out there - my evil twin who is undermining every move I make."
...Mr. Waits said there were two kinds of imitation. "I don't mind if someone wants to try to sound like me to do a show," he said. "I get a kick out of that."
"I make a distinction," he added, "between people who use the voice as a creative item and people who are selling cigarettes and underwear. It's a big difference. We all know the difference. And it's stealing. They get a lot out of standing next to me, and I just get big legal bills."
This is a pretty Overt stance, but as you may remember, Tom Waits is Second-Stage Advanced, which looks a lot like Overt. He started out Advanced (he must have been Overt before he started recording), then has gotten more and more Overt. But it isn't true Overtness because if you are Advanced, everything you do will be Advanced as well. You might be shaking your head, but you'd have a pretty hard time convincing yourself that Tom Waits doesn't belong among the Advanced.