Stephen de Vries writes "Mac OS X is one of the most secure default installations of any OS. But it is still possible to lock the OS down further, in order to meet corporate security guidelines or to securely use network services. Corsaire has released a guide to Securing Mac OS X Tiger (long pdf) which addresses the new security features introduced through Tiger and presents some security good practice guidelines."
If it happens once, it's a bug. If it happens twice, it's a feature.
If it happens more than twice, it's a design philosophy.