So item one, If you are on a Commercial flight and it has 50 or more people on it
You can pretty much be assured that someone on the flight has been to jail at least once (Simple US rates of jailing)

There are some specific standards in transport in these types of cases
If you see someone and they have handcuffs in front and no leg chains you can pretty much assume them to be rated non-violent

Its only when you see a single person escorted on with hand and leg chains and escorted by 6 LEO's and there is a row in front and behind of everyone that you start to wonder about things...

At the end of the day the LEO's transporting the person want to be safe and not have any drama's even more than you.