What influence does Crane-man have over Tree-ear's decision to not tell Min about Kang's idea?

Crane-ear's answer to Tree-ear's question led to Tree-ear's decision to keep Kang's idea to himself.

"If a man's keeping an idea to himself, and that idea is taken by stealth or trickery— I say it is stealing. But once a man has revealed his idea to others, it is no longer his alone. It belongs to the world."