Even in the best of situations you can still get burned. A poor choice that breaks trust but is not necessarily bad character. I have had that happen as well. A Dom that we had a great connection, good trust, boundaries and everything seemed fine. But he made a choice to be dishonest and that broke the trust we had achieved. It was was unsalvageable.
It is a delicate balance I find. I don't want to be cynical and distrusting of everyone. I take people and face value, and give them enough rope to run with.. or hang themselves with. Time eventually tells.
I think sometimes it is easy for subs to get "starry-eyed" and miss the signs as well. They want a Dom so badly that they overlook small details and become entralled with the idea of being owned, without considering the cost of who owns them.
Dishonesty and bad character have other symptoms as well. Inconsistencies, missing timelines, etc. Even players cannot mask that for very long. So I think it is about the communication and consistency of a person that helps me to know if they are real or not. Does what they say and what they do always add up.
Just because there are players out there does not mean that I am going to become a suspicious, distrusting person. I can be wise and careful, but at some point you have to be willing to risk as well. As long as those investments of risk and reward are equal on the the part of both parties in the relationship. . . an exchange.