i saw it as an example of a new type of justice - proper justice - one we'd all like to vent on those scumbags who seemingly get off lightly - make the criminal relive similar - the idea that standing and watching is almost as bad as committing the crime - and they had turned into some kind of theme park thing, for people to join in with.
i dont really see how they could have doled out that sort of 'justice' to all criminals though... so she was singled out.
they are mainly just cautionary tales, this one the culture of the bystander - all those people who stand by and film wrongdoings instead of intervening, or who cause bad things to happen specifically in order for them to film it.
not sure when it was supposed to be set - how far in the future - though i did notice the tax disc in the van was oct 12 ... that was probably a continuity error though