And take a second to read the vote sharing rules: For instance, providing a valid e-mail address will quintuple your vote.
I have a good dozen valid email addresses, but since I use the same real name with all of them (and I always identify myself, why waste my taxes to have the government spend extra effort to find the author of my subversive opinions?) I only use one of them for voting.
Besides, casting multiple votes would be unethical, even if they don't specifically prohibit it.
And they might rightly choose to disregard suspicious votes if unusual activity is detected.