I have and I think that it is both ridiculous and interesting. I love tattoos and I have several. People notice them and ask me about them all the time. What do they mean? When did you get it done? Did it hurt? etc. etc. So why not jump on this opportunity to advertise? In a sense, it is a fantastic way to get brand recognition, but it could serve as a downfall for the individual with the tattoo. You get paid for the advertisment, but how much is enough to permanently tattoo yourself with a company logo or advertisment? What happens if the company goes under? There is a LOT to think about when it comes to it.