Yup, I felt the same way.
The teacher added an "assignment" called "Cell Phone Use" to the calculations at the last minute (literally after the quarter ended and right before the end of the grading window) worth 100 points. So, the possible score for "summative score" went from about 550 to 650. Most of the students were given a bonus of 100 points while my DD received a 0. I know of one other child who was given 50 points instead of 100 but the teacher contacted her mother part way through the quarter and she straightened up and flew right and only lost half of the bonus. So, different kids doing the same thing were handled differently. *sigh* What's funny is that this all happened just about a year ago as 3rd quarter just ended.
It also rubbed me the wrong way that the teacher was so happy that she got my DD's attention with the punishment. The teacher promised to "work" with my DD and if she did everything perfect in the 4th quarter she would get an "A" but that didn't happen. She did stay off her cell phone, LOL.