I think the point is it's a standard documented format -- you can probably come up with something much shorter if you don't care about this particular format.

I think the point is it's a standard documented format -- you can probably come up with something much shorter if you don't care about this particular format. We've been using a custom 12-character format where the first character is a type and the last 11 characters is a random int encoded in a base-62 alphabet (url safe, no punctuation, etc) -- this gives us ~17 billion billion combinations -- almost 64 bits.