Well in all fairness, I would assume that most API's and Services have some form of disclaimer.
What TOTALLY 100% open service have you ever seen?
What TOTALLY 100% open service have you ever seen?
I realize that "legit" is a subjective term, so well, that is why TOS for API's are needed.
Actually, you can (and should) build protections against spam and improper use into the protocol instead of relying on a centralized gatekeeper. All truly open systems do this.