The most dumb kidnapper?

I am surprised I don't see any people talking about this. Possibly the biggest flaw of the movie, unless I missed something. At one point during the movie the trunk is open and Michael clearly hears Jordan talking and you can even see him reacting to it but he doesn't act on it at all. Even before all of that though, how are you NOT going to make sure the person you are kidnapping has nothing like phones on him/her? Pretty sure in real life 911 would not be receiving such calls.