Homoerotocism between Trent and Sean
There's a scene at the barbeque where Trent sticks his finger through a hole in Sean's shirt and rubs his chest, and then later at the confrontation in the road Sean kisses Trent. These are both quite a surprise, not least because both are carried out in front of other people suggesting that he was quite open about his love of Trent.
I can't work out if these are supposed to be real gay attraction on Sean's part or are an alegory for the gated comunity's hatred of 'trailer trash' to the point that they can play with them in any way they want.