We do not intend to train on them, no. This never even occurred to me to address in the rules. (What would be the point? There will be few good submissions and they would be a vanishingly small % of existing training data and this doesn't seem like a super-valuable task in general that would make a LLM that much more valuable...)

Personally, I would encourage participants to publish their pieces independently. Note that we only require a non-exclusive CC-BY-NC license for the ones we select as winners, which is intended to allow people to republish the good pieces themselves, especially commercially.