I think to a large part this is the fault of the airport, which could easily mitigate these mistakes. One, two or all three of these things could eliminate all but the people who are really, really stupid:
1) Put prominent signs about, especially around and in front of the security areas, to remind people of this rule.
2) Periodically play a recorded message over the airport intercom about this rule.
3) Have mention made during baggage check in, when they ask you the other questions about your baggage. “Did you pack your own bags, and have they been under your control since they were packed? If you have a weapon such as a knife or handgun or other prohibited item, please do not attempt to pass through a security checkpoint with it in your possession, or you may be subject to arrest.”
That overlooks one uncomfortable fact: the constitution guarantees the right to keep and bear arms to the people via the 2nd amendment.
The 2nd has not been amended or repealed; therefore, it is not unreasonable to claim that such rules/regulations/”laws” are null and void because they alter the amendment in “unofficial”/”de facto” manner: the right of the people to keep and bear arms shall not be infringed, except in the cases of: air travel, train travel, presence in a schoolhouse, courthouses (appearance for jury duty notwithstanding), and any place that someone complains about guns making them scared.