Yes, you can't force everyone, but I would bet that most people would take shelter given the right incentives/exception from negative consequences.

As I said, people are people. Most people I know drive over the speed limit, because everyone does it, and because the likelihood of it hurting them is low. Same principle here. I'm all for everyone going to the shelter, just as I'm all for severe penalties for going over the speed limit. Most people, though, are OK going over the speed limit but not OK with people not sheltering when there's a tornado. It's almost always the case that such people have never lived in a tornado zone and cannot comprehend the dynamics of the situation.

Funny you say that. One my my current responsibilities is chemical safety (it's written in the offer letter), and recently I contributed to a colleague getting called on the carpet by HR. I have no doubt that were there any serious injuries in any laboratory HR and counsel would wish to talk to me, and I have no desire for such a conversation.