Whatever people are doing, they’re doing it wrong. My postal code is a four digit number with a leading zero. Quite a few online forms and stores explodes when I enter it. Even if they allow me to enter it, the shipping label is often wrong. The leading zero is often printed as a binary blob of nonsense, a Unicode replacement character (U+FFFD), or another weird Unicode symbol. Or the zero gets unceremoniously moved from the start to the end of the postal code. It’s not uncommon for the zero to be dropped and the other three other digits to be repeated, creating a new non-existing six digit postal code. I almost forgot that once a store insisted I enter my postal code to confirm my login, but it refused to let me login. I eventually guessed that the Unicode replacement character (U+FFFD) followed by the remaining three digits would let me login. (My last order had contained that character on the shipping label.) Programmers suck at planning for and handling the leading zeros.