How to prevent someone from entering strings without making it available for translation?

There is no way to know if string should be translatable or not (should a 'fail' in a json response be translatable?). Some things just need proper code review and can not be automated.

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)