Some airports do ask you if you are carrying more than 10k in Cash.....Few years ago, a Korean Guy in front of us had lied, but the sniffing dog got him. He was carrying less than 10k, but told the USCIS Officer 500 USD....when he was in fact carrying 7800 in cash........he was let go, but more than 10k is a risk if the airport you are traveling through has similar security measures for international flights.....If you are traveling with a partner or a friend....its always safe to split the amount so each of u have less than 10k each......