The group in the middle is the group I'm talking about. At the far edges of stupidity are the sort of criminals who break into an electronics shop to steal GPS tracking devices or try to stick up a police station. The far extremes give you 1000 ways to catch them instead of 100.
The guy who carries his phone with him during the commission of the crime is the guy at the median.
It also doesn't hurt that the average criminal skews dumber than the average law-abiding citizen to begin with. But even for the somewhat above average criminal who gives you ten ways to catch them instead of a hundred, you still don't need eleven because you only need one.
What do you suppose the percentage of criminals is who are so diligent that having default insecure communications is the only way to catch them and they wouldn't have chosen a secure alternative regardless?