Full text from SAG-AFTRA:
You cannot participate in conventions on behalf of or to promote companies we are striking against. This includes appearances, panels, fan meet and greets, etc. involving projects produced by struck companies, whether current or past, and current and past independent projects that are not signed to an interim agreement.
You may participate in a convention in ways that are wholly independent of your work on struck projects and that are not sponsored by or connected to struck companies. Additionally, you may participate in appearances, conventions, and fan expos for work under contracts other than the TV and Theatrical Agreements, such as TV or New Media animation or video games. (Theatrical animation is struck work and you cannot participate in events relating to animated theatrical content during the strike.)
Important tactic, but i do feel bad for the cons as they are usually entirely separate (and much smaller) entities from the studios that make the content.
I bet they would be well supported if they opened up donations (if that hasn’t already happened). From what I have gathered, the community funds that WAG and other unions manage have been incredibly well supported so far.