Business Calls

Received a message on my business answering machine from a mom asking about themes for her 8-year-old daughters party. Put together a list and called her back. I was a good mom. I waited until the kids were all in bed. They were read to, sung to, tucked in, music turned on, door shut, down for the night. How did they know I was on the phone with a potential client, trying to sound professional? How did they know that tonight was the night to come out of their room (something that all three of them together rarely do) and try to talk to me, all at the same time? How did they pick the exact moment that I was on the phone with said client to whine and cry and try to do things in my room that they are not allowed to do?