There is a way that isn't to dangerous. Get yourself some very large rounds of wood. About 20" dia. by 24" tall or larger. Position the saw on it's side, with the saw off. Figure out the a arc of bar if where to kick back sideways. Position the other round of wood to stop the movement of bar. This only demonstrates tip kick back.
I only do this part throttle so show first time chainsaw user what tip kick back is. A good visual aid would be to outline the tip of bar where there is high kick back potential with a red sharpy.
I have not figured a easy way to demonstrate push and pull kick back.
What I described "IS HOW I SHOW KICKBACK". Do at your own risk!!!
One good teaching point is to get new users to learn how to hold the handle bar properly. Meaning locking their thumb under index finger.
I know that most of us cut with a saw just to off to the center(right side) of are bodys. Most of us know or have had training dealing with kick back. I am comfortable cutting that way.
I teach newbies to cut slightly off to the right, keeping the bar arc alway from their body. Is not the most comfortable or natural stance, but if a newbie has a tip kickback. More then likely they are not going to get hurt.
My .02
Mike