I lied about my daughter's age once. We went to a beautiful rustic island camping ground that has a beautiful spring-fed hot tub and sauna. When we went down to take a soak we saw a sign saying "No Children Under The Age Of Six."
My daughter was 4.5 at the time, and had been looking forward to having her "swimcuzzi" for several days.
I figured, "Oh, what the heck is this! I know she is safe and mature enough for a hot tub," so we went in. As we entered I whispered for her to tell anyone who asked that she was six years old (as if anyone would have believed it).
We were there for 45 minutes and met some great people, none of whom gave a crud about the age of our daughter, of course. They thought she was quite charming, and asked her what her favorite color was, what her favorite food was, what school she went to, and... how old she was. Uh oh...
"I am pretend six years old!"
she proclaimed loudly, looking over at me with pride for having remembered what age she was supposed to be.
I quietly died of embarrassment in my corner of the hot tub while everyone around me roared with laughter. Then we all commiserated about the silly age rule in the tub.