The Examiner should .....
in JAR / EASA speak is simply a recommendation, not a mandatory requirement.
If the applicant passes, I consider that any incorrect answers should be specifically debriefed ("Question nn you answered b and the correct answer was c - you added variation in the wrong sense", or whatever. Otherwise you will never know whether he/she ever understood what he/she had answered incorrectly.
If the applicant fails, you could say something like "You need to practise use of the computer" or "Read up more on radio aids" or something similar as appropriate.