Ever wonder how much of our lives is being captured on videotape?

More than you might think. Every time you walk into a Wawa. Or for that matter, most stores and banks.

Part of the time you spend behind the wheel. At some intersections. Every time you pay a toll. Crossing a bridge. Entering parking garages.

If you ride mass transit, guess what? You’re increasingly on candid cameras.

For the past few days, the region has been appalled at an unprovoked attack on a SEPTA subway train in Philadelphia. A man got on a subway train for for no apparent reason took out a hammer and started beating a sleeping passenger nearby.

And, yes, it was captured on videotape. Police released the tape to the media, in hopes that it would spark information about the man who so brutally beat his fellow rider, who appeared to be dozing while listening to an iPod.

It worked, in no small part to the videotape, which has been played again and again on local TV stations, and been plastered all over Web sites, including this one.

In the post 9/11 world, we have learned that there are times when our privacy may be infringed in the name of security. Just where to draw that line is debatable.

What is not is that increased use of video cameras is effective. In this case, it led to the arrest of a man who didn’t blink an eye, even with his young son in tow, when he walked onto a subway car, deposited the boy in a seat, then took out a hammer and started flailing away at an innocent passenger nearby.

That’s a trade-off I think we can live with.