Bank managers have robbed their own banks whilst their kids were held at home, at gunpoint!
So
in my last airline, what's your point? If you are suggesting that aircrews are vulnerable to external pressure you are quite wrong. If you were capable of such an act, you'd apply use it against a security goon and not to someone who will be in the air. Coercion such as this has to have a offer the promise that you'll see your loved ones again in return for your compliance. Everybody now knows what happens when the bad guys get in the aircraft. An additional reason for picking on security personnel is that the reliability of their rosters means that not only could you easily follow them home your planning would be made a lot easier.
And then consider this. The average security guard at an airport is not doing their job to protect their country or fellow man. They are doing it for exactly the same reason that I work - to put a meal on the table. Yet unlike most other people, few choose this job out of choice, it's out of necessity. There aren't many other jobs they could do. Which therefore means that security guards are even more vulnerable to external criminal pressures. And what additional checks are made on security personnel? I'll wager bugger all with no additional profiling or spot checks on their family life either. And if any checks are done, the security personnel remain vulnerable because the bad guys don't know these are done.
No, the greatest threat to the security of aviation is the security system itself.