I think that anything like the picture posted earlier is downright careless. To a much lesser degree, I think that a yellow ball sticking out the top of the pants is somewhat sloppy. Under "Use of the Penalty Marker" on page 18 of NFHS mechanics, it should be "tucked out of sight." Look at youself in the mirror if you tuck yours in your pants. The yellow detracts from your appearance, IMHO. I prefer white tape (never heard of the black); if the flag's tucked in all the way to the ball, the ball blends with your shirt, not your belt.
That's my .02 with change leftover
Jonathan