It already doesn't work.

Weckert tested the shirt using Yolo, an open-source, real-time AI object detection system.

Tested one of the images from the article here: https://playground.roboflow.com/models/ultralytics/yolo26 which detects a person just fine.

(It's already a bad sign that it was tested with "Yolo" and no more details about version/variant/size)