Canada

The whole point in an emergency is to get the official guidance out to where people look first for information, not retrain them to go to official sites.

What you are suggesting is that Facebook and Twitter be legally required to push official emergency information from governments to the top. That would parallel what the broadcasters and cable carriers typically have to do. It makes sense, but given that they don’t seem to want to be obligated to carry government information except as paid advertising, this would require a new emergency system for internet platforms.