Given that the entire principle of asymmetric warfware, of which "terrorism" is an element, is based on attacking the enemy where they are weakest, the TSA effectively serves no function. If the enemy reinforces security at one location, attack another. It's a fact that you can't protect all locations all the time. There will always be weak spots.
Right now the weak spot is you usually have thousands of people hanging around outside the security gates waiting to get screened. Maybe they should have a pre-screening area for screening people who want to go into the screening line to make sure they're not going to do any terrorism!
The thing is, an attack in a queue could happen anywhere, not just an airport. But the effects are highly localized. Part of what makes plane bombs extra-scary is that they could go off anywhere, so not only does the plane blow up, but it falls out of the sky and lands on people. That's more terrifying than a bomb explosion in a fixed location, plus it impacts all other travel arteries, giving the travel network in question the equivalent of a heart attack. A bomb in the air causes a lot more problems than one on the ground.
So of course it serves a function, however badly it does so. They overstepped in this case, but I don't have that much sympathy for the artist. He knew quite well that what he was doing looked like a dry run for a bombing; I'll warrant he just didn't expect to actually get arrested.
The thing is, an attack in a queue could happen anywhere, not just an airport. But the effects are highly localized. Part of what makes plane bombs extra-scary is that they could go off anywhere, so not only does the plane blow up, but it falls out of the sky and lands on people. That's more terrifying than a bomb explosion in a fixed location, plus it impacts all other travel arteries, giving the travel network in question the equivalent of a heart attack. A bomb in the air causes a lot more problems than one on the ground.
So of course it serves a function, however badly it does so. They overstepped in this case, but I don't have that much sympathy for the artist. He knew quite well that what he was doing looked like a dry run for a bombing; I'll warrant he just didn't expect to actually get arrested.