- It must not contain anything inappropriate or otherwise offensive. We go by US decency standards, sorry.
In fact, federal obscenity law in the U.S. is highly unusual in that not only is there no uniform national standard, but rather, there is an explicit legal precedent (the "Miller test", below) that all but guarantees that something that is legally obscene in one jurisdiction may not be in another.
However, I recommend not continuing to use the phrase, but instead replacing it with something like "material considered inappropriate or offensive will be disqualified, at the judges' sole and final discretion".
That over with, I look forward to submitting my entries.
-Arlo