People reason from their own narrow experience. Not surprising but knowing this, as we all must, it's useful to take a cortical-thalamic pause now and then to consider the implications of events for others having quite different experiences. It’s illegal to be a goth wirehead.

“They were arrested for behavior that was suspicious and disturbing,” said Lt. Gregory Reinhardt, a police spokesman. . .

A friend of the group said the arrests were overkill and that the suspicious devices were homemade stereos. “This was just kids trying to have some fun,” said Helen Hicks, who said she has attended similar “zombie” gatherings in the past.

This kind of story illustrates to me the reason why it’s better to just throw up your hands and give up on proactively protecting society from terrorists than to follow through on what it takes. The argument goes something like:

Suppose you are going to watch carefully for terrorism. Ergo, you will waste resources when there are things that look like terrorism but aren’t. Ergo, you can be inefficient, or you can pass (and enforce) laws against looking like terrorism. Unfortunately, lots of harmless things, like making your own backpack stereos, being interested in rocketry, and the many other similar overreaction stories we’ve seen, look like terrorism. Ergo, innocent citizens lose the freedom to do harmless things, or at least the freedom to do them without fear.

Every since the Murrah building in OK city was blown up with a fertilizer bomb it has been hard for folks with legitimate needs to get the stuff. Ammonium nitrate, like potassium nitrate and calcium nitrate is explosive. The ancient formula for black powder is a 6-1-1 mix of potassium nitrate, charcoal and sulfur. No news here.

Ammonium nitrate and calcium nitrate are highly prized as top dressings for permanent pastures since they are "ready to eat" and don't acidify soil. In situations like this where you can't realistically incorporate fertilizer into the soil - it's not tilled - ammonia, or urea which goes through an ammonia phase as bacteria convert it to nitrates, is inappropriate. Ammonia is a gas which wafts away into the air when used as a top dressing. You have to get it below ground somehow in order to avoid double digit losses on a daily basis.

That problem has been solved now that ammonium nitrate is mixed with 6% dolomite lime (calcium + magnesium) before sale. It doesn't explode. But it was a problem for years. But the fact that this explosive that had been in common use for hundreds of years was made unavailable for a time though it caused hardship for many innocents is another example of the ineffective yet onerous costs of seeking to proactively protect society from terrorists.

Terrorism is no reason to set our tails on fire and run in circles. That, after all, is just what terrorists want.