I think the only thing for Mr. Wheaton to do was keep walking, (as much as possible) wave graciously, and say loudly, "Thanks for coming, I'll be signing autographs later at X/Y!"
If he has to hire bodyguards to help with this, then that's just a cost of doing business for him. It's sad he has to do so, but it's better than being completely overwhelmed.
As long, of course, as they don't turn into the Patti LaBelle thugs at IAH.
Seriously, he was right to call them out on it, and I think the best thing for the future is to make it clear, nothing will be signed from anyone who acts this way. Anything else encourages people to become entitled stalkers.