Has anybody ever collected under any of these schemes?
When I was in fifth grade, I had a cruel teacher. He told the class of 30 students, that if everybody got 100% on the weekly spelling tests, he would take us all for a day at the local amusement park. Of course, this was impossible, as in the class we had one girl who was dyslexic, and two Puerto Rican boys who could barely speak English.
While spelling scores did improve overall, the girl rarely got more than 5 or 6 right out of 20 words, and the Puerto Rican kids didn't do that much better. But what it did was make these poor kids the object of anger and ridicule from those who got 100% on the spelling test.
The teacher knew that the likelihood of 30 kids getting 100%, even if none were dyslexic or non English speakers, was zero.