The projects with suspicious stars were still >80% nonfake stars. That to me suggests that most of the fake stars have been classified as nonfake. There isn't much psychological value in boosting your star count by just 25%.
>>lozeng+(OP)
Depends on when the fake stars were created. If they are early in a projects life cycle, they may be used to get attention on the project, and once they have awareness, fake stars are no longer necessary.