It's not. YC has no such terms that I am aware of. YC says this in regards to IP/ideas, though: Will you sign an NDA? How do I know you won't steal my idea?

It's not. YC has no such terms that I am aware of. YC says this in regards to IP/ideas, though: Will you sign an NDA? How do I know you won't steal my idea? No, we won't sign an NDA. No venture firm would at this stage. The informal commitment to secrecy on our application form is more than any VC would make.