It's only a Y10K problem if people assume that a year that happens to be 4 digits is existing in a system that doesn't permit years of 5 or more digits.
But as soon as you put a leading 0, (besides confusing people) you seem to be telling people to definitely use arbitrary fixed lengths for years and analogous purposes. Even though they weren't necessarily doing that before.
Honestly I don't know how date parsing code coped back when we ticked over from 999 to 1000, a lot of monastic accounting software must have shit the bed.
Anyway I'm creating the Long Long Now Foundation to solve the shortsighted 5-digit year issue. Look for more news in Q000001 of 002026
But as soon as you put a leading 0, (besides confusing people) you seem to be telling people to definitely use arbitrary fixed lengths for years and analogous purposes. Even though they weren't necessarily doing that before.
Sincerely,