I can’t blame any organizer who hasn’t yet cancelled a conference scheduled for April or May. They hold out to the hope things will improve until then. That doesn’t mean they won’t cancel. It’s easy to say they should act differently if it’s not your salary that is in danger.

IMO hope will not help. As a conference organizer you have the duty to cancel in respect of other people’s health (not only talking about the attendees). So the real question is what could an alternative formal look like, that will minimize your risk of monetary damage.