Ending spoiler: No way they'd get away with it.

It's interesting that in the end you see the parents were as stupid as their kids: Bret's dad threatened everyone into committing a ridiculous, over-the-top reaction, and the other parents blindly followed him in committing a terrible crime.

But, I'd be interested to actually see what happened next because there's no way they'd get away with the nonsense they pulled.

1) As others have pointed out, it's wasn't just the blond kid (Cooper/ Ryan?) who died. In the forest there's one kid in the road, another beaten to death and another with his head burned. There were no asian people in the party so I'm assuming the Asian kid's (Adam?) parents have already called the police. The parents are also not part of Bret's dad's entourage of chavvy morons and so are not part of Jenny's death.

2) Assuming the other parents of the dead children are at the party, how long until they find out how their kid's died? How loyal will they be when it turns out Bret set fire to some kids head or punched some kid to death? They could try and blame Jenny and Steven for all the kid's deaths, but I highly doubt anyone would fall for that.

3) There's evidence everywhere. Deleting videos off your phone doesn't mean they cannot be found again and there's bound to be loads of blood and DNA on the kids and victims. Plus, Bret's swaggering around with those sunglasses (as well as who knows what else) which ties him to the victims.

In all honesty, had this been some police/investigation show it would have been more interesting and the outlandish stuff would have been slightly easier to swallow as lots of those shows usually end up having pretty bizarre conclusions.