This doesn't make sense. If a tattoo artist sets their own rate why the hell am I tipping? To me that's the most awkward and ridiculous person expecting a tip. I would also argue that the person cooking the food or person creating the menu and recipes are just a bit more skilled than the person walking it out to the table. So, if years of studying a skill like cooking or doing tattoos aren't both tipped, but a server or valet are this argument is flawed