Hackaton ideas - sure, hackaton code - no thanks
There is nothing wrong for an idea from a playground to challenge the organization.
Provided that the idea does not come attached to a pile of spaghetti code produced in a bout of junk food and caffeine induced stupor.
Unfortunately most organizations fail to realize that hackatons should produce ideas and the attached code is usually a PoC to show the idea works. Instead of discarding it and rewriting it from scratch they attempt to sanitize and productize it. In fact, this is actively encouraged at most hackatons I have seen (It is also why I refuse to participate in them).