10k USD here is nothing. Would I bring that to Shenzhen or China, nope. But I wouldn't worry about having 10k, keep in mind where your connections are too, I would say having cash is probably only safe in Japan, HK, Taiwan, Korea?, not sure about the rest in Asia. Keep it in sight in your pocket or a backpack that you keep in your lap. Now if people see it, then you're in trouble. Lots of theft on international flights, but they usually go to watches and diamonds, and a guy recently lost a couple million worth on a flight to HK. So don't be that guy.