In twenty years of sports competitions on Nationstates, the expectations with regards to puppets are clear: You should declare any and all puppet nations you enter into a tournament as belonging to your main nation. To purposefully do otherwise might be construed as anything between trolling and cheating.
However, as this is not an expectation anywhere else on the forum, this general guideline is not a forum-wide rule, and is not in any way enforceable by the mod team unless the first post of a competition explicitly states something along the lines of:
Puppet nations must be declaredAND
There is a maximum of one puppet per user
If your thread has specific rules about puppets in its OP, the mod team can act to notify or warn users that are, accidentally or not, transgressing your competition’s rules. If in doubt, you can paste the above example into the OP of your thread.
This is a call not only for hosts to be diligent but also for everyone to be vigilant. If the OP of a thread does not contain anything about puppet rules, or includes the above rules only in part, it is very likely that some participants, potentially including hosts, will intentionally enter multiple puppets into the competition. This regularly happens in long-running major tournaments that are not explicit about their internal puppet rules.
In order to bring this type of behaviour to an end, please be vigilant and inform hosts whenever they've omitted puppet rules from their competition, and treat competitions that continue to omit puppet rules with caution.
For a full run-down of how puppet rules work, see here.