The reason safety guards and authority states exist is because of the incompetency of the average person. We all have seen cases of the naive individual who falls for some email scam, or even a street hustle. Everyone is just too ignorant and/or not cautious enough.
Anybody can be caught up in a scam--anybody. I've known some very, very smart people caught up in scams (e.g. pickpockets and the like). Just because you are smart doesn't mean you spend every waking hour looking for ways people can scam you--as scammers do.
The reason safety guards exist is because we have this cool "civilization" thing that allows us to have specialized professions, freeing most people to pursue their field rather than needing to know ever single one of them.