It's mindsets like that which cause things like this to happen in the first place. FYI before everyone high-horses on the I'm the protector of your privacy and freedom spiel none of that junk protects my little girl when an extremist decides to bring an explosive to a public event.
*scratches head* About the only thing that actually does protect in that situation is to not have public events. Period. Secret to everyone, there's not actually a way to stop that sort of thing if someone genuinely wants to go through with it. There's always gaps. There's always a way to exploit them to do harm. Physical protection is inefficient and generally quite imperfectly effective. It has its place, and a certain degree is reasonable and up to a point worth the cost, but at its core this sort of thing is not a question of security. It's a question of motivations, values... what causes people to do things like that and how to demotivate them from doing it without substantial negative effects. And physical demotivation... deterrents, security, etc., so forth, so on has... thresholds. Points of decreasing efficiency. Points where going beyond a certain degree of implementation backfires and
increases motivation. I won't go so far as to say the states are there yet on the domestic front, but... there's a lot more to be pissed off about than there was a decade ago, I'd say. Especially considering how at odds invasive security in general is to a good chunk of the American ethos.
But yeah, it's going to depend on what happens next on the civil liberty front. Given what's happened since 9/11 and how the fear culture has been propagated and exploited, though... it's understandable that folks are kinda' preemptively worried. Hopefully the reaction will be sane and
effective.