Good point.
I think part of the fascination with the balloon incident was that it was about a child, and that there was speculation that it was a hoax and people tried to figure out on which side they came down. The parents did a pretty good job of predicting the public response, I'm surprised they didn't end up in jail for that trick. Let's hope none of their kids ever really gets lost because I'm sure the authorities will assume that it is just another grab for attention with possibly disastrous results. Don't cry 'wolf' when there is no wolf...
The media would most definitely freak out over a mall shooting, but mall shootings are not that rare today (right now google news has 650 items linked to that theme), especially if it involved guys in non western clothing.
But it would not be on the same level as 'shoe bomber tries to blow up airliner', at least I would think it wouldn't be.
If the terrorists really were simply out to kill you, which route would be more effective do you think? Blow up an airliner with a relatively small chance of success with a bomb straight out of some spy novel or to smuggle an armalite in to the local mall and let loose?
Can you see malls with body scanners in your future?
Schools with body scanners?
I'm sure the people selling that stuff would have their wet dreams come true if someone tried that.
In NL here we had a craze some years ago where some crazy injected a few oranges in a supermarket with mercury. The media took it and ran with it, causing all kinds of copycat incidents.
The funny thing is that mercury is relatively safe as a fluid, it is when it is in vapour form or when it is part of a reactive compound that the trouble begins.
That didn't stop an all out panic though, fueled by an uninformed media milking it for all it was worth.