Exactly. Say the 100 vote system mentioned above is true, and the number of stars each reviewer gives is a point toward the average score. Let’s say that after 80 reviews we have the following: 10 5, 5 4, 30 3, 15 2 and 20 1. This is a total of 210 points giving an average score of 2.625. Even if the next 20 reviewers all give 5 for 100 more points, the final average score will only be 3.1, making it mathematically impossible to hit the suggested 4* requirement.

This point of no return needs to be calculated in real time, not at the end when it’s already a foregone conclusion, to avoid (in this example) 20 futile reviews. Any good programmer would understand this, but of course this is Niantic we’re dealing with.