This was last year, the student in charge came out with the student who was walking around in the testing center. They tapped his shoulder and picked up his test and they walked into the room where you exit. The student in charge came back and started to look at the kids water bottle and it looked like he had written a bunch of stuff on the inside of the label.

Also I had a good friend who worked at the TC for years, when they banned food we asked her about it and she said that they caught a group of students communicating with each other using skittles or m&m's or something. They had a color system for abcd and they would shift an m&m to the outside corner of their desk, when they all agreed on a color and an answer they would eat the m&m and move on to the next question. Seems like that would be incredibly obvious and easy thing to catch honestly.