I think the hope is that people coming here to learn and do free translations (work) for the web are not typically trolls, and that those who are trolls will be outvoted by the benevolent crowd :-).

Why worry?

I also think there is a person or people who give negative votes to questions for no apparent reason. This also happens at coursers.com. I give questions a positive vote to help neutralize this when it happens.

I would hope they have a method to catch "toxic graders". If someone does this a lot, they would spike in any kind of counts I would think.