[psquid]

Unfortunately, I suspect you overestimate the obfuscating power of dynamic content when the number of users is sufficiently large.

A certain MMO I play recently had a limited-time event built around figuring out the meaning of different clues (locations to go to for the actual meat of the event), and despite a fairly large number of variations, people had collectively figured out just about every possible clue->location mapping within a matter of hours.

That's not to say you can't prevent cheating, but that even with relatively little incentive (that whole clues thing gave only a single cosmetic item, and anecdotally I've seen very few people actually use theirs) users can and most likely will outpace any attempt to prevent it by means of varying the problem.