I believe that you can use an anonymous certificate, although
I think that there are some restrictions on what you can/can't
do with them.
That is a good use for Anonymous certificates. Their potential
shortcoming is if/when ACL's are used for secure meetings (very rarely
done so far). If I were setting up a secure meeting room, my first
general "deny" rule would be aimed at any Anonymous certificate. Mind
you, I'm not sure that thats possible with the current ACL's, but an
ideal system should "allow" or "deny" classes of certificate such as
Anonymous.