Which blockchain? bitcoin address has no names, one entity can own billions of bitcoin address if that is what you mean. What I say is based on my experience playing on this website.
Sure, but how do they get the winning seeds? They also prove that nothing is fishy. My user ID is in the low four digits, I have been playing there for years, and also never went over the third winning level. But with the millions and millions of users, these win posts are more than realistic. And as I said, the blockchain is proof.