In the last several weeks I've seen it happen too many times. Parents that yell from the sidelines instead of getting close and helping their children. Or they yell at the slightly older sibling to take care of the younger one. I'll give you an example.
We were at the beach in Puerto Vallarta. The area we were at had a short beach so playing meant either being in the sand or fairly deep water. There were two little girls holding hands and playing. One looked to be 2 and the other maybe 4. I am terrible at guessing ages, but the younger one didn't talk much, but could walk well. So they are playing and they get kind of close to the water and go in a bit. The father yells from about 20 feet away for them to get back to the sand. He's not moving toward them, he's just yelling. So finally, he walks over to them and starts yelling at the older girl that she has to watch out for the younger one. He tells her that she can't swim and the tide would just take her away and she would be gone. She was 4. This man expected a 4 yr old to care for a smaller child. I don't trust adults to care for my 16 month old how can he put that on a 4 yr old's shoulders. I was disgusted.
Later on we were walking in the area of the girls playing and they got in pretty far. The mom was nearby with a drink in her hand not really paying attention. The dad started yelling again from the shore. My husband ran over and grabbed one of them and pulled them back to shore. The mom finally decided her child was worth saving and grabbed the other one. Of course the dad started yelling about how they shouldn't be in the water. WTF? Husband and I agreed that the kids were probably not in any danger as they were not in too deep, but he said the kid he grabbed looked pretty scared just the same.
If your child was almost swept away by the tide, wouldn't you go sprinting after them? Well, most of us would be close to them in the first place, but still go with me here. So after you got them, wouldn't you hold them close and be happy to have them in your arms? Wouldn't your first thought be 'thank you'? Wouldn't you then tell them that they scared mommy and daddy and they need to stay in the safe area?
I've seen lots more just like this. Absent parenting. You don't have to be paranoid, but at least try to participate.