SLD starting with digit (or containing only digits)

Janos,

I would be grateful if someone could tell me what problems could arise by permitting domain names starting with a digit, or even containing *only* digits, under a TLD.

FYI There are already lots of zones registered under .com with two digit names... 00.COM. 01.COM. 02.COM. 03.COM. 04.COM. 05.COM. 06.COM. 07.COM. 08.COM. 09.COM. [ etc...] So you wouldn't be the first to do it. Regards, Chris - RIPE NCC.