[Agema]

A way to make enforced NAPs without mods would be to have the game organiser enforce a penalty on a NAP-breaker.

He could change email and therefore withhold the .trn file from the offender and enforce one or more staled turns; as a step further even access the .trn file himself and pay the victim gems or gold from the NAP breaker's treasury (although not if he was playing himself as he'd also get unfair advantage info on the nation); he could give the offender's .trn file to all the other players so they'd know exactly what he had; in really severe situations he could simply kick the player out and get a sub or turn it AI.

It's not impossible they could do a rollback when a complaint was made, access the turn and either undo the attacks or enforce a stale instead, but it's much less fuss to to create a punishment far worse than any advantage gained by the NAP treachery.