It's a fine line though, isn't it - obviously we want politeness and respect for elders but we also want our kids to be able to speak up when they're in a situation where things aren't right. It comes down to life experience for them to be able to tell which 'wrong' situations are to be protested and which you just let slide. While DS figures it out himself you're just going to have to keep telling him each time.
Surely if you any confidence in yourself as a professional you can handle the critique of a smartypants 8 year old - I would have been embarrassed too but slightly interested in their reaction as well to be honest
