If we could reliaby detect sociopaths, they would probably face stronger incentives for behaving tolerably well.

This could in fact be a key reason for smarter psychopaths being less likely to commit crimes. One article in the series simply states that subjects will "us[e] cognitive resources to devise nonviolent means (such as conning and manipulation) to get what they want." However, in practice, conning and manipulation do not really work very well. The strongest effect may just be that smarter psychopaths are using their smarts to compensate for their deficits in empathy and behaving in a more pro-social way: this is consistent with social science research, which shows that smarter folks are more economically rational and more likely to respond to incentives.