LEOs develop an intuitive ability to spot "bad guys" simply by being on the job long enough. It helps a whole bunch of them stay alive to go home to their families at end of shift. But it's also a double-edged sword. While they can spot the bad guy, actually doing something about it without further probable cause is where they can get into trouble. And yes, sometimes they are wrong, but most times they are correct. I would imagine that it's very difficult for them to walk away from somebody they know is a bad guy.
Most of these bad guys will not comply to LEOs orders - lawfully given or not. They generally pay a much higher price for their non-compliance.
"Good guys" comply and live - even if it means their rights are compromised and they have to get it straightened out in court.
I have been stopped, disarmed and questioned by different Police agencies many times - simply because of the hours I've been out at night thanks to my work. In every instance the LEOs explained their actions sufficiently to help me understand why they took the actions they did. It was usually just an inconvenience and used up valuable sleep cycle time. My compliance and demeanor toward the LEOs during our contact went a very long way towards diffusing any hostilities between armed men in the wee hours of the morning. Being reasonable, compliant, coherent and sober appears to go a very long way.