that is a drawback, but all you have to do is create a login and the problem is solved. it's a compromise for sure but the problem is, one bad apple ruins the whole system, and as soon as you launch, one bad apple will come along and vote 20 times on a story by clearing their cookies. so, for me, 1 vote per IP for cookie based login or ignore IP for logins has worked out well for me. i haven't officially launched the site yet, and when i do, i am actually leaning toward requiring logins but i'll play that by ear.