DDMMYY-XXXX
Hmm... that seems to put a hard limit of 10000 IDs/day, assuming that they start with 0000 and push straight through to 9999, something which sounds... unlikely, if only for the way that it’d make life easy for certain elements of society. Adding two more Xes would make things much harder to fake. And would leave space for popuation growth.
Biting the hand that feeds IT
