Would you give me your Social Security Number if I asked for it? Why not? Would you give it to your bank when opening a bank account? Why? When you join a comp

Would you give me your Social Security Number if I asked for it? Why not? Would you give it to your bank when opening a bank account? Why? When you join a company, you have to sign a NDA that covers not only the company's trade secrets, but any trade secrets of that company's partners that you are exposed to. So, Microsoft is somewhat free to share their source with select partners whom they trust will keep it secure, and only share with employees who need it. I don't think Joe's Software LLC would have been able to get the Windows source code, even with an NDA.