To be honest, I did not know anonymous accounts could vote 
I’m somewhat tempted to just disable voting for them, idk
You should actually have a 6 vote limit, and probably most anonymous accounts will have 2-4, but technically any user should be able to obtain up to 12 on their own:
I’d be more concerned about people using this to double-vote on the same topic than bypassing the limit, but I think hopefully most people just won’t do that.
Forum staff actually have no mechanism to see which account owns an anonymous account, so they’re “truly” anonymous in that sense, making this hard to enforce. To be clear, I could see who owns it, so don’t treat this as a pass to go nuts, but it would require some manual database queries which thankfully I haven’t had to do thus far. The community has handled anonymous posting very well.