Exactly how do you think that someone is supposed to evaluate translation work in a language that he or she does not speak?
based on time and experience, sadly they can trick both of them very easily
There are negative ratings for abusing stuff like this, and this thread was opened in order to determine whether the accused should receive one or not. Using Google translator to post translations is bannable but only when it's clearly just c/p from the tool.
things have changed, it's very easy to change automated translated text, cosmetizing the translation with few clicks and synonyms(
"just c/p from the tool" )
of course we can not pretend the same thing when the "translator" is not a native speaker ( but these situations are very rare, I think )
but:
things are very simple, everyone, translator, user etc, has a specific style to interpret/understand ( spoke and write) the text from a foreign language => genuine/original/natural translation
only Google Translate generate the same syntax, it's so easy to catch someone who is using automated translation software.
they can't change the whole text even if they are trying to customize it.
I can say for sure that Google Translate ( for Romanian Language) has an accuracy of 40 - 60% ( this applies only to ordinary language not to technical language which is more "tangled" )