I think you have found a good way to authoritatively catch people using automated translation tools, and that is to use automated translation tools to translate the post in question, and if the translated post is sufficiently similar, I think most would agree the post was translated using automated translation tools and should be removed accordingly. If you note that you used google translate in the report, it would be much easier for a moderator to handle the report as opposed to saying that someone is using words in a strange way in your native language.

The argument that someone is using automated translation tools is almost always subjective, although there are some cases that are more clear-cut than others. What may be a clear-cut case to a native speaker may be too difficult for a non-native speaker to understand.