To the non-vigilant who choose to not be onguard even though they know the area they live in contains all kinds of terrorists, ya has got to be smarter than that.
To the terrorist bringing a knife, the old saying don't bring a knife to a gun fight is still pretty much true.
Especially if you is not dealing with a bunch of non alert people who are oblivious to their surroundings and apparently the area they live in ....