Not trying to keep this off-topic (though, not trying to put it back on) but yes, it's possible. Sometimes it's really easy, especially if you're not the parent. The parent has many roles in the child's eyes, while a grandparent, a stranger on a plane, a teacher, etc., typically have one, which is that of an elder's authority.
I'm fortunate to have two kids who are completely different. If I had two like my first, I'd think as you do, that you can just ask. I'd also think that my parenting methods were near ideal. However, I learned quickly that we're born with a lot of who we are. Kids (people, really) respond differently to guidance. My first can be asked to do something, told why, and that's it. Maybe a firm voice if it's not sinking in immediately. My second isn't the same.
That said, I did find something that works with regard to seat back kicking (see, I'm coming back around). I gave the car a personality. Sparky has a deep voice and is very friendly. And Sparky does NOT like to be kicked. It doesn't make him mad, it just makes him really, really sad. So my seat backs are actually in pretty great shape most of the time.
TL;DR - we're all different. I don't judge parents or kids based on my personal experience, nor do I assume the same tactics will work with them. But.. there's almost always some way to get through.
