Translation quality policy?

Yes, this is generally the policy in practice. If a use clearly makes many bad translations, contact them on the talk page. If help is needed from an administrator with revoking translation rights, blocking, or deleting many bad translations, bring it up right here on the Support page.

Very helpful Amir. Indeed, while the lack of mandatory reviews is not without merit, cases where volunteers fail to catch mistakes early make it seem like the project has a preference for poor translations over missing ones :(