Have you witnessed any other incidents at the airport where someone made a bad joke and had to face serious consequences?

Have you ever had to live with an unwanted animal in your house for an extended period? How did you cope with the situation?
Why do some people think it's okay to joke about serious things like weapons at airport security, and what's the usual outcome of such jokes?
Can people with selfish motivations still be considered as contributing positively compared to those who do nothing? How do we assess that?