I’ll leave aside for the moment who accidentally brings a on through an airport security check. Heck I don’t even keep a mini-multitool in any bag I might casually bring on as carry-on, somewhat to my annoyance. But if you do happen to have an oops firearm in your carryon I’m not sure I care if it was a mistake or on purpose.
I'm not saying those guns shouldn't be confiscated. I'm just saying that how much they confiscate says nothing about their capability to confiscate gun brought with malicious intent. There's way more stupid people with guns than malicious ones.