I try never to carry condoms on my body ever. In HK there are so many convenience stores around. In China, I buy them at the late-night pharmacies after I cross the border and buy only brands I know. If you are caught in China, you could always claim that you are buying them in China because they are cheaper than in HK.
I always leave any remaining condoms with either the last wg I see in China or with the last buddy scheduled to leave China.
One night I went to meet up with civi girl and it was late. So I could only find my favorite condoms either sold in a box of 12 at a 24-hour supermarket or in a box of 3 sold at the convenience store. I figured I would go for the best value and buy the box of 12.
After the session with the civi girl, I offered the girl the box containing the remaining 10 condoms to keep for next time. Shit, she didn't want any condoms lying around where her family could find it. I could throw away a box of 1 or 2 condoms but not a box of 10! So I took them back and stashed them for next time.
Aiyah, next time I will always go for the smallest box as there is no value after all with buying too many!