Why cant people just ask?

Last night me and my two friends Christian and Nick were hanging out at my new house. We had just walked back form 9th street park it was about 10:30 pm. and we were kind of hungry. My moms friends had just made dinner so we ate, and I have to say that its actually really good. I was impressed. After we ate we decided to go outside and skate around in the street. None of us were aware that it was past curfew. So without the thought going through our minds we just skated up and down the street. About an hour later we were sitting on the curb around the corner from my house. I saw a cop drive past us on Military, and it seemed like he was just driving down the road. So me and Nick screamed "cop!" and ran trying to scare Christian, but we didn't realize that the cop was turning around to come talk to us. Us running made it look like we were up to no good. We knew we had to go back for Christan. We walked around the corner to see Christian being sat on the ground by the cop. When i walked up he told me and Nick to sit as well. We had to explain to the cop why we ran. We said that we didn't think he was going to turn around at the light to come into the complex. Thats when my mom walked around the corner and saved us all. She started talking about how she was the lady that the cops had to help get out of hand cuffs at her friends house, and how she had a lamp shade on her head. I wasn't embarrassed because its my mom and stuff like that is kind or normal for me to hear. The cop said "if you're going to run as a joke wait till you cant see the cop car anymore and wait until you're sure the cop isn't in the neighborhood for you." Then he paused and said "you know just don't run at all." No more waking up people that can get up to call the cops but cant walk outside to ask us to keep it down or go inside. Nicely of course.