Comment 17 for bug 812728

Apologies in advance if this is slightly off-topic: reading the blueprint, a theoretical workaround is to disable the guest account (ie since the menu appears whenever the system allows a guest session *or* when there is more than one user account).

However, I cannot find a way to do this (I looked in the user-admin and the old users & groups admin as well as the dash but without success; looking in Synaptic I thought that gdm-guest-session might be providing this functionality, but it isn't, and ubuntu-questions hasn't been able to provide an answer yet.) Does somebody here know how to disable the guest account?