"So I created Register and Privileged subclasses..."

Hmmmm ... since that seems to be the only difference in users, registered and non, why not instead add an attribute to your user class? Just a simple boolean flag, is_registered should suffice. Now, i do, however, make seperate classes for "users" and "administrators" ... but then again, i also only allow "users" to access the files in a directory called /user -- whereas "admins" get full run of the board.

You might want to consider how Anonymous Monk is handled here. All users who come to this site are Anonymous Monks until they login. That is ... they are already a user, that user simply has less priviledge to do things, like post to the CB.

L-LL-L--L-LL-L--L-LL-L--
-R--R-RR-R--R-RR-R--R-RR
B--B--B--B--B--B--B--B--
H---H---H---H---H---H---
(the triplet paradiddle with high-hat)