Just goes to show how a helicopter parent, of which they're many, can turn off an AO and potentially undermine a child's chance to be admitted.
The interview is the least predictable, big influencer in the whole admission's process. An average kid on paper who sparkles in the interview will often see a thick envelope long before the brighter, more accomplished kid who was "bleh" in the interview.
Parlabane's Six Interview/Tour Rules for Boarding School
1. Get your parents (or an adult friend) to pretend that they're an interviewer and ask you some typical interview questions. This gives you a chance to figure out what YOUR opinions are and to practice articulating them. This is NOT a memorization exercise for canned responses (ugh!). It's just a general readiness exercise.
2. Know about the school where you're interviewing and why you would like to attend THAT SCHOOL. Memorize 1-3 questions that are the most important to you to be answered, specific to THAT SCHOOL and any other questions you wish to ask that would apply to all the schools you’re visiting. REMEMBER, this is a two way process. You need to learn as much about them as much as they need to learn about you.
3. Firm handshake and eye contact. Direct, authentic, engaged.
4. Smile, smile, smile - and feel free to laugh if something's funny. You can’t begin to appreciate the power of a ready smile and a positive attitude. It changes everything!
5. Have fun. This is the attitude to take at all times! Don't be scared. Let the other kids be nervous, you're there to have fun, meet someone new, make a friend. Get in this frame of mind no matter what it takes. (Note to Helipcopter Parents - you know who you are - lay off, this is the time for your kid to be who he or she is without the added pressure of pleasing you.)
6. Write a thank you note to the AO (parents should too).