As a frequent flyer, with lots and lots of miles, I became accustomed to flying up front long before I had kids.

So when I had kids, I wasn't going to suddenly feel like sitting in the back. No way. I'm tall, and I like to eat. So I upgraded my kids (on their own tickets) when we traveled, and I still do, now that they are older.

Of course the kids don't know the difference between F or J and cattle class when they are infants, but so what? I certainly know the difference.

Above, I mentioned that I like to eat. When you upgrade (or redeem award tickets for) the kids, you get that many more meals - in the past I have eaten 3 complete F meals - yum. The FA's look of disappointment was priceless when I told them "I'll have the filet, this child (about one year old) will have the salmon, and that one over there (also about one year old) will also have the filet."

Why collect lots and lots of miles if you aren't going to use them?