Rule #1: don't start a business that depends on data owned by some other business.
Rule #1-1: especially if your product adversely affects the other business.
Rule #1-2: especially if the other business is much larger than yours.
Rule #1-1: especially if your product adversely affects the other business.
Rule #1-2: especially if the other business is much larger than yours.
As citizens we should oppose this concept of data ownership; you shouldn't be able to 'own' facts that the public and your employees already reasonably have access to.