I must say I'd be a bit weirded out if I ever saw a young Japanese kendoka rip offf his (or her) gi to reveal a Eureka flag on their arm.
Others... VB logo, Holden HSV, Centrelink customer number, and the Somali flag. I live in a Bogannic/Somali area.
Me? Tatts? Nah. Like the others have said: my taste is too changeable.