the shadows cast by ones hand....on the image on the arm will be very distracting.......
other problems such as the aforementioned arm hair and shadows may come to mind...
scam comes to mind I can tell you that
Kinda eliminates the full sleeve tat crowd from their Facebook and Twitter sites.
Then again, on the othet hand so to speak, projecting a slide show on one’s arm could eliminate a few cases of hepatitis and a whole lot of god-how-drunk-was-I-when-I-did-that morning after regrets.