why could he not post as bluebell?

I'm sure he could. And, he could post his next node as redbell, and a followup as tinkerbell. The following day he could post as libertybell, bellcurve, and bigben (well, that last one might be a little close to home for tilly, and best avoided.)

In other words, when someone uses a registered account, he is doing so for his own convenience, not yours.

Having an Anonymous Monk account is also a convenience. It is convenient for people that want to post anonymously. It is convenient for people that just stop by and don't want to register an account. It's also a convenient way to reduce the number of orphaned accounts.

-sauoq
"My two cents aren't worth a dime.";