I can think of two reasons that someone ends up with a callsign consisting of only numbers.
a) The system asks for an ID consisting of alphanumerical characters. Now, "numerical" is easy to understand, but that "alpha", well, let's best ignore it.
b) New user types in his password...
I think I noticed someone (can't remember, was just a number

) talking about using his cell phone number. Maybe there are some other reasons to choose a number. I would be 206 if WB3 had allowed numerical characters
