The feeling I've gotten whenever I posed a question to the ABC Rules Committee is that the rules ARE intentionally vague to allow broad interpretation. It would be difficult to explicitly address every specific rules infraction and their variations.
In ClutchClay's case with the denatured alcohol user, the rules do cover the situation - it's not a legal cleaner. And it's up to the bowler to be aware of the rules, or at least consult with someone more familiar with the rules (or better yet, look at the rule book itself!) in order to obtain a judgement. But as Ragnar implied, do it quickly. IIRC, you have 15 days in order to file a protest. Personally, I wouldn't file...but not because of the fear of being ostracized. After the fact, it would be very difficult if not impossible to prove that the person in question used an illegal cleaner that night. So there probably is little to gain in filing a formal protest. Now, however, I would make sure that the entire league was aware of what the legal and illegal ball cleaners and polishes are and when they can and cannot be used.