I guess we could say the knife cuts both ways. What guarantee does a person have buying oil that claims to meet all certifications, yet doesn't participate in the program?
It is real easy to say you meet/exceed when you're not a member of that group that bothers with the API certs, because it costs too much. At least the major oil companies have some guidelines they have to follow, and have the API to answer to.
Notice I didn't mention any company names? There's a reason.