[juujian]

Meanwhile, friend of mine's last name was Li, and IDs were first initial + last name + #

Her number had three digits.

I'm guessing it's the birthday that really messed the system up though?

[SoftTalker]

Very common last name for Chinese and places like universities usually don't ever re-issue a username. So the "first-initial + last name + number" approach can get into triple digits easily.