Not really, because such sites really only use upvotes/downvotes as a ranking mechanism. There's theoretically a lifetime upvote/downvote counter (ie. your karma), but other than a number that shows up on your profile, it doesn't have any real impact. You don't really develop a "reputation", for instance your comments get more or less visibility based on your previous commenting history.
There were a couple occasions on Reddit where someone replied to me in seemingly bad faith. I looked and they had negative karma. As a result, I didn’t engage.
But I will agree that it’s far from perfect. It’s also similar to the bar example. A reputation is built one person at a time. It takes a while, with repeated bad behavior, to build a bad reputation with the entire staff or regulars.
> other than a number that shows up on your profile, it doesn't have any real impact.
Certain subreddits you can't comment on until you have a minimum # of karma, some other subs auto-ban you if you contribute or subscribe to other subs.