The comments here are pretty stupid. Apple allowing access to source code is a basic thing. Microsoft also allows access to source code to large business partners.
Personnal example, we needed Outlook not to go through American servers, because of the size of our business, they allowed making a server elsewhere (Canada). It cost a lot. But if you believe that your internal data and the data of your clients is confidential, you can't just say yes to external software, or cloud services. You need to be able to make an audit and see what is going on. Costs a lot? You bet. But what happens if your customers lose confidence in you? How much cost to your reputation if your data is hacked?
I would let them audit too if I were Apple. The reason is simple: China's huge market! Why work against the local government when your intention is to sell more product, and this applies to other countries not just China.
@Andy Chow There is a difference between allowing Canada to check the source and allowing China to, considering that 9 out of 10 copies of Windows are pirated and the LARGE amount of iPhone clones that pop up from there. Hell there are even Chinese copies of BMWs and other cars, they clone and copy anything they can get their hands on so showing them how your OS works directly is a bit dangerous.
@Andy Chow, and you are so clueless. It's like allowing a robber into your house and check-out its weakness, and plan for an attack later. Or allowing a copycat, study your technology, how good is it, and make their own.
Doesn't anyone remember what happened when China wanted to see the source code for Cisco IOS and they agreed? Long story short....Huawei got there source code free and changed it partially to look like it was created by Huawei. Apple is stupid enough to agree to this?