As we try to point out to competitors (and critics of unlabelled photographs...), late entries not only create a massive amount of extra work for organisers and officials, whether voluntary or paid, but they make any future historian's job a total nightmare. Not so long ago, a programme would have to be produced by a printer and maybe even typeset, so late entries (if they were even accepted) would never be in the programme.

Late entries is very much a Kiwi thing, not just in motorsport. Scan many old UK race programmes and every race has a list of reserves. If you didn't get your entry in early, no chance!