You got no official warnings, just a warning to stop. That's all that is needed I think, I doubt you'll ever repeat the behaviour so you will probably not be in trouble because of it anytime soon. It was just a misunderstanding. I indeed assumed it would be quite clear that it would be wrong to rate your own and other's reviews (double) using another account. If the system does not allow you to rate a review twice or rate your own review, why would you think it would allow it using a different account? I thought that would be clear but I guess I'll find a place to clarify it.

And the review rating doesn't influence any stats yet, but might in the future. It already influences how many people will read it since they will read the reviews higher up the page first, and also will take advice from higher-rated reviews faster.

We are busy writing up a detailed JCF rules page. J2O already has one but it's not very detailed (it's just a pointer to what rules we apply, not an official page containing all our rules or what the admins are allowed to do, etc) and will probably be extended to include rules like not rating your own downloads or own reviews.