I had thought the reverse - that psychopaths schemed very carefully to get what they want, manipulating the world around them with great patience and foresight. But perhaps that is just a stereotype.
I dont know about that, people are not alert to them most of the time and I dont think its not unreasonable that they arent, especially if the same individuals have been clever enough to take up particular positions in order to carry out their crimes, in fiction there's Dexter, he's a forensic scene of crime officer, in point of fact some psycho like or at least conscienceless individuals became priests or exploited the positions of priests in their communities in order to carry out predatory acts.
I would question whether or not its realistic for the average individual to be totally vigilant and on the alert all the time to these kinds of people, the psychology is totally different, its a little bit like saying why cant wilder beast be more like lions, that is with none of the conventional disrespect of wilderbeast either, they are living their lives and I'm sure they are good lives but they arent lions and cant be expected to live accordingly or as a lion.
I've known a lot of victims of predators and my reactions to them are that they could be any of us, they arent morons, the people they dealt with are not evil genius' either, although they were something different to what the survivors thought they were and they behaved in reprehensible ways that no one could really be expected to be on the guard against in the normal run of things.
Consider the guy who was responsible for the bind, torture and kill serial killings too, that guy wasnt a criminal mastermind, he was just someone no one would suspect.