Whenever people complain that the world is getting more dangerous, and talk about how it's not safe to let their children play outside in the way we used to as children, I point out that it's not necessarily the level of danger that has changed, but the level of reporting.
Here in the UK, we can name each of the children who has been abducted and murdered by a stranger over the last several years, because the disappearance of a child has been the trigger for wall-to-wall coverage by all of the electronic and print media.
Similarly, when there have been incidents such as yesterday's shootings in Virginia, worldwide coverage and comment has been instantaneous and extensive, and the incidents and their victims are remembered for years afterwards.
As soon as reporters heard that tennis player Andy Murray was from Dunblane, they latched onto this and soon worked out that he must have been in the school when the shootings took place there - so he is frequently described as "Dunblane shooting survivor Andy Murray".
As long as the media make such a fuss about events like this, we can take some comfort from the fact that they are rare, isolated incidents. That's what makes them news - things like the daily carnage on the roads and the daily death toll from abortion are not newsworthy, because they happen every day.
Out of idle curiosity, I just searched Google News for any reports of the Tesco shooting in Thornton Heath that Mac mentioned yesterday. There weren't any. Now, maybe nobody was hurt. But I'm sure there was a time when the criminal use of a gun in a busy public place in England would merit the odd column inch.
For that reason, perhaps we should see the Thornton Heath episode as more worrying than the Virginia Tech incident. It's tragic that these people were brutally murdered in Virginia, but the incident was a one-off, and nobody seriously expects to encounter a madman on a murdering spree on a daily basis.
The Thornton Heath episode was a piece of casual brutality and criminality that has become so commonplace in Blair's Britain that we would never even have heard of it if it weren't for Mac's friend actually having been there. The fear of such incidents affects the way people live their lives on a daily basis. Because it's not reported, the government feels able to ignore it - even on occasion to blame us if we become victims of crime (for 'flaunting' our possessions, for instance).
Do we really have to wait for some incident with higher 'shock value' before the deterioration of our society and our quality of life is ever addressed?