The Charmed Guard

Previously: Dealing with Evil Adventurers

A typical scenario in fantasy TTRPGs: low-level PCs need to gain entry to the palace. The guard will not let them in. The PCs use some minor enchantment magic to get past the guard. The guard is later confronted by their incredulous superior. The superior decides this is some kind of inexplicable lapse in judgment from the previously reliable guard, and punishes them accordingly. The PCs chortle at the chaos they've sown and move on.

DMs tend to treat NPCs as rubes unaware that magic exists. And some number of rube NPCs is probably a good idea. Commoners, tradesfolk, and castle guards are not going to be proficient in Arcana or know the ins and outs of specific spells. But with the exception of explicitly low-magic settings, regular people would be very aware that when something really weird happens, magic should be considered as a possible explanation. And organizations should respond in a way that demonstrates this awareness, so that the DM can create credible challenges for the PCs.

When something really bizarre happens, or someone does something completely out of character, NPCs should seek to gather as much information as they can. Outsiders will always be scrutinized because they have a short track record, especially if they are ostentatious or conspicuous adventuring PCs (heavily armed, magic-wielding groups usually including non-local non-humans should almost always be assumed to be conspicuous unless they are going to considerable lengths to be inconspicuous). PCs will be, at best, asked many questions and watched. At worst, they may face all kinds of harassment and scrutiny just for being people reasonably capable of disrupting normal life.