OK, I did some more research and I think I have found a way for guest users to read our posts but not be able to post/quote/reply/create new threads.
This should allow people who wish to read what is here without registering to do so. I apologize for the temporary lockdown this morning and to the 9 users who registered as a result. However, welcome aboard!
These settings should also prevent any more spambots from using the guest user loophole to spam us with weird Chinese spams.
Let me know if you are locked out of anything as a result of my changes. If you cannot post to let me know, email me at firstname.lastname@example.org