There can be false negatives (in this case failure to detect unsafe driving behavior), but a positive signal of extended phone use while FSD beta is active could be enough "evidence" to kick someone out. Unclear if it is nuanced enough to determine that distracted behavior while sitting behind another vehicle at a red light is not as unsafe as higher speed driving with pedestrians nearby.Dirty Tesla has a 3 and said he has it blocked with tape. So that can't be the only measurement used.