Here's a case where the guy probably regrets getting that tattoo. The government used it against him in proving that he unlawfully possessed a weapon.
The case is United States v. Greer, decided on February 4. Egged on by a government informant, Greer decided to rob a house. The informant told the police to look out for Greer's car, a Hyundai Sonata. When Greer realized he was being followed, he ran away from the car and hid out in someone's house. Looking in the car, the police found firearms and ammunition. As someone with a felony record, Greer was not allowed to have any of this. The police also saw that the car was rented to Tangela Hudson. One of the detectives saw that Greer had a tattoo that said, "Tangela." Since Greer was not in the car when the police found the unlawful weapons, the tattoo allows the government to link Greer with the car, which contained the weapons.
So what's the problem? Greer says the detective's testimony about Greer's tattoos violates the Fifth Amendment right against self-incrimination. The Court of Appeals (Walker, Cabranes and Koeltl [D.J.]) agrees with Greer that the tattoo is "testimonial" in that it does convey a message. "The government relied on the tattoo not as an identifying physical characteristic but for the content of what was written. The tattoo was therefore testimonial and, because it linked Greer to the ammunition, incriminating." So far, so good for Greer. He wins that battle.
But he loses the war. While the tattoo is testimonial and therefore implicates the Fifth Amendment, the government was able to use it against Greer at trial because the tattoo was not compelled by the government. Remember, the Fifth Amendment prohibits compelled self-incrimination. "No evidence supports Greer's contention on appeal that officers were able to read the tattoo only by applying physical force during his arrest. And [under Supreme Court precedent], even if that were true, it would still not amount to compulsion for Fifth Amendment purposes." Since the tattoo was Greer's idea and not the product of governmental compulsion, the government can use it against him, and the conviction is upheld.