Here's a "What Would You Do?"
You're going to an amusement park. Kids 11 and under can ride half price. Your child is 12 but is so small he can pass for 8. Do you pay full price or lie for the discount?
My parents lied about me to get the discount. I always looked young for my age, until life's luggage took its toll.
My kids, on the other hand, never experienced us lying to get them in cheap. We just didn't want to introduce them to moral fluidity that early in their life. As adults, they don't lie about their kids' ages, either.