Next time you should make the wording for the rule more clear, because
Only submissions for this jam are allowed
sounds a lot like
The lifespan of an onion is determined by how long it lives
: one could think
¡Of Course only submissions for this jam are allowed; otherwise it wouldn’t be a submission for this Jam!
in the same way that they would think
¡Of Course the lifespan of an onion is determined by how long it lives; otherwise it wouldn’t be the lifespan of an Onion!
. much better is something like
Submissions must be just for this jam and not for other jams
.
