Would this even be a problem for most scenarios? I don't think most users have (or would want to spend) the time to look at two browsers for every set of comments I want to view and/or vote on.
This is a hacker community. It will take all of 24 hours for purpose-built bookmarklets or even browser extensions to appear.
Seeing vote counts could also be a karma linked feature, I suppose. That makes it enough work to the point where it's probably not worth it to game the system.