With many partners, distinguishing accidents from betrayals is not worth the effort.

Evidence

Of course, the trigger strategy can be misguided in some cases in which there is merely a mistake and not an exploitative intention on the part of the other. On the other hand, when there are many alternative potential partners, there can be too little benefit in trying to distinguish mistakes from anticooperative intentions to justify the effort, and so we simply move to an alternative partner. — Russell Hardin, Trust and Trustworthiness, 440