“ In this dungeon, the monsters will not be hostile unless you take something without permission. If you do take something, the monsters inside will consider it stealing and attack you.”
“ The PCs are sent with a diplomat to another country to protect him and do his bidding. There may be some espionage, rescuing, downright bullying, etc. Could make a nice medieval, special operations background.”
“ The creatures in this dungeon will not become hostile so long as you do not cause any trouble inside. If you provoke them though, you aggro the whole dungeon. If the players are smart, they can complete the dungeon crawl without having to fight anything.”