Let's not get too far into the Chip Debate. That's a larger issue, and we're still in the Dark Ages technologically.
I'm just trying to work on the identification of riders by officials, spectators, and other riders.
Actually, I'm just trying to get away from pinning my teammate's number on while we're standing at the start line.
We could color code the bibs very easily, but when an official scores a race by hand (which they're still required to do), you can't have identical numbers in the pack even if the background is a different color because they're writing the numbers down in real time (though some rely on video to capture the passing peloton). It's too much to write down. And to that end, they only want to score two-digit numbers which is why they want entire fields in one number sequence when possible.
That's why they don't want, for example, a 35+ rider racing in the P-1-2 who wants to wear his 35+ number which is Yellow 135. And he's riding alongside a P-1-2 rider wearing White 135. The official would pull out a gun and shoot one of them dead rather than have to score two 135s.