Noah WARNED everyone about the great flood. The people of the day, which would be Twitter users in today's society, just laughed him off.
Moses tried to warn Pharaoh and his cabinet about the incoming plagues and eventual heavenly smackdown he was going to receive if he didn't soften his heart. We all saw how that turned out.
I guess my point is that is it still worth it to try to wake people up even when we know they're not going to listen and will do anything it takes to maintain their cognitive dissonance? Lots of biblical precedent gets me thinking about this on a daily basis.
Noah didn't have well publicized people dead daily--each sudden death causes a chain reaction