On a different note, my takeaway from this story: pick your battles.
Sure, you can go into an airport with $11k in cash. Maybe you're a Sikh and you want to carry a kirpan [0] into the airport, or you're a high school kid working on a science project and you have a bunch of C-cell batteries taped together with wires hanging out the ends of them (experience talking).
You're probably increasing your odds of getting stopped. Sometimes it's worth it, maybe for strong religious beliefs, or you feel strongly about the exercise of your democratic rights. But fighting the collective weight of "normal", shared perception, culture, etc. is costly. You'll be delayed, people will ask lots of annoying questions, in general you'll expend a lot of energy on stuff that is in some sense, entirely avoidable.
I felt this way recently when trying to get a loan for a house from Wells Fargo. Quit my W2 a few months ago for a large contract. I couldn't convince the bank my income was solid even though the payment was about 1/8th of my taxable income and I had almost the entire mortgage balance in semi-liquid retirement accounts. Sometimes the message the world sends is, "conform".