If the plane was on fire, filled with smoke, I don't think the risk of "criminal offense" is going to change anyone's behavior.

It's a run for your life at that point.

I vote for making it a criminal offense, but I highly doubt any of the passengers are "trained" to not do that. Being told to do something is barely "education", and it is definitely not "training".

Perhaps people should be taught that aircrafts are dictatorships. The crew of a ship has legal authority over passengers. The politely-spoken comment, "federal law mandates that you follow crew member instructions" in their 5 minute briefing doesn't seem to stick out to anyone.

In the US, it already is, insofar as it is a knowing and willful violation of flight crew and/or flight attendant instructions. I imagine that generally similar laws are in place in many other jurisdictions.