In most of these type of places I wouldn't go 'on a mission to score'. When I was very young, I'd do that sort of thing and risk sketchy situations. But that's in the states where I don't have to worry about getting whipped and jailed for ten years. I'd be chill about it, if it comes to you so be it.
I'd never have more then I can swallow or shove up my ass. Even so I'd guess they'd take you to a police station for a drug test. Maybe you could argue it was already in your system before you arrive but that might just make them mean. Beat you until you puke up the stuff you swallowed. Or give them a reason to find the stuff you keistered. Even so if it was offered I'd probably let my curiosity get the better of me. I'd be in a hurry to puff up my stash though.
I thought that they are strict in China.
They are but it's still around, I've heard in all the major cities. The better you know Chinese, the more friends you have, the better. Talking to people from East Asia, they've all told me something very important. Regular people consider it a low class thing. The way most people here look at homeless crack heads. The idea is that only dangerous gangster criminals or despised outcast minority groups like the Uighurs do it.
I had a close friend from Laos, he'd go back there and wouldn't score for this reason. It's something uneducated villagers do, his family and friends there would think he was crazy if he brought it up. He'd lose all respect in his community. I'd keep this in mind, it's very important for how people view you and gives you an idea of what the cops who bust you are thinking.
One of my biggest regrets in life is not going to Laos with him. He moved, I lost my phone, don't know how to get a hold of him. He was a great guy, we also had a Filipino friends we'd hang out with. We'd smoke tons of ganja, Filipinos especially love to toke. They'd say the stuff in Manila was terrible, they'd smuggle back some green bud and everyone would want to smoke it.
My friend's grandfather wanted him to go back to Laos to get initiated into his Buddhist religion, become a man or whatever. He didn't want to go because he'd have to shave his head and fast and meditate for a month. I was so close to volunteering to join him, for the experience and to help him get through it. One of the best things he said, the Westerners who think they're Buddhist have no idea what it's like. It's not this happy little laughing Buddha bullshit. It sucks to grow up in it and have to deal with your family's beliefs. I know that's universal.