I am aware of the challenge. That is why I say that the sharing and fairly broad collection of information for the purpose of identifying threats is reasonable provided that, once the information is analyzed and leads to the conclusion that the vast majority of people do not pose a threat, it is destroyed. That way, security agencies will not have numerous profiles on people who are not threats.
It is fine to begin with a funnel-like approach and focus on a certain number of people, many of whom are not threats, and then come to an appropriate conclusion. Therefore, once it has been concluded that the vast majority of those people are not threats, their information should be destroyed.