I know they cannot upload an avatar anymore. But, we just had a case where a banned member was using Gravatar, and their avatar was still displaying on the forum. Usually not a problem, but this banned member changed their Gravatar to something nasty in order to get back at us. We went in and deleted his Gravatar email address (which was different from the email he used to register), and the Gravatar is gone.
This does not seem like proper behavior of the forum software.
Have I missed a setting somewhere, or is this something that might be a bug? I couldn't find anything relevant in a search here. I would think that a Gravatar would be disabled upon banning, although I can see how that might be difficult to implement without wiping out the Gravatar email field upon banning.