Hmm, that still seems like a silly practice. The custom today isn't 4 digit years anyway; it's whatever number of digits you need and no more. For example, we say Vesuvius erupted in AD 79, not AD 0079. We'll naturally switch to 5-digit years in the year 10000 that way without needing to put a leading 0 on every year in the meantime. And 5 digits seems arbitrary anyway: what happens in the year 100000?
