It's silly regardless of whether or not you know Japanese/Chinese. They're the most cliched tattoo you can get. Often-times, kanji tattoos that may look or seem cool to a westerner will look rather silly to a native speaker of Japanese/Chinese. People treat kanji as if it's some cool, mystical language that no one understands - it's just a silly trend - and kanji is just an alphabet. Do yourself a favor and get some real artwork done if you want a tattoo.
Hanzi Smatter 一知半解 <-- go there and see the terrible mistakes people have made getting kanji tattoos.