It's definitely a trade-off we're making in terms of a laid back society versus a hypervigilant society.

I saw an unattended soft attache bag in a grocery store one week. Of course, as paranoia shidoshi, the possibility that it was a bomb set to blow in the soft target of a supermarket did cross my mind; however, I also knew that it could belong to some sales rep who was around the corner straightening the potato chips. So instead of alerting the manager, and perhaps getting the store cordoned off for a bomb threat, I let it lie. And it didn't explode.

I'd assume the parks service people operate with a similar modus operandi. They assume that the logical explanation is something other than "It's gonna blow!" and in most cases, they're right.

However, perhaps some day one will. At which point, of course, the vigilance and effectiveness will be questioned, probably too much. Fortunately, exploding bags are not so commonplace that they have become a default assumption. I hope they never do.

As such, this incident smacks of Gotchaism. There's really no difference between this "test" and the kid who smuggled boxcutters onto airlines. As long as our society remains free, we'll have more holes than strands in our safety net.