Planet Fitness

The contract states no children under the age of 13 years are allowed in the facility. The last 4 times I went to work out, there was a kid sitting by his or her parents. They were not bothering anyone. I didn't mind at all. The kids were maybe 10 years old. Definitely NOT 13. So I figured, they broke the rule for these people, I would bring my child with me to sit by me, while I worked out. But I was rudely, and I mean rudely told that I was not able to bring my child with me, and that I had to leave. I had just walked in the door. I told them I understood the rule, but why were the other children allowed to sit by their parents. (The kids were not there this day.) The woman said they never break the rule. I told her I had seen it numerous times. She said I was mistaken. I don't mind being turned away for trying to break the rule, but if I see another kid there, I will be complaining very loudly. Why favoritism?