On a par 3 playing over a lake, I bladed a 5 iron and hit a bird swimming on the lake. It was really sad because the bird flopped around on the lake for a while before expiring.
I'd rather say that it was the people hitting into the waiting players that caused the dangerous situation, not the players ahead. We don't know who was ahead of those on the green. Regardless, you should not hit into anyone. After the second time I'd be having a talk with the players hitting into me.