As a Cop I can tell you the cops were mainly relieved. We go on these all day long. Normally kids playing on phone, dialing India, etc. When we can go on a call and there is nothing wrong (and no paperwork needed) we are happy.
Funny story. I was sitting at home watching TV my kids were in thier rooms playing. A knock on the door a friend is at the door in uniform. They had a 911 Hangup at my house. We go back to my youngest (4 at the time) sons room. He had received a little informative book that had buttons on it. when you pushed in 911 it made siren sounds and said help was on the way. He just had to try it out for himself. It seems that They notify EVERYONE when a 911 call comes out at a officers house. I brought the book in to work with me to explain that it was all a misunderstanding. It happens to everyone.