I don't request a check for every translation: I'm requesting a check of the first one, might skip the next one and then request a check again for a third one to avoid too much checking work because I don't want to bother anyone too much. By doing so, I try to catch abusers because a check can happen any time and that went well so far but if you say it's really a garbage translation, many thanks for your hint and I'll request an improvement.

Actually, we cannot blame you for that because once you see someone already translated your topic and it was good, naturally you would like to allow him to translate more of your topic. But whoever you contact to check the translation, did they ever mentioned that it seems the guy used automatic translator? At least did they doubt that?
If I translate a topic, I should understand what I am writing. Autometic translators never be able to do accurate translation. You should ask someone to check who has some experience or you can trust.