This might happen more than we know. Some parents just don't go to the media.
A friends son has been accused of being a "possible school shooter" 2 years in a row during the first week of school each year. He is guilty of being white and skinny. The jokes are always from minorities and it winds up scaring female students.
Last year he got caught up with a few students talking as some students said he looked like a school shooter. He didn't take it serious and they all joked about it for a few minutes. Another girl over-heard and got scared and alerted administrators. They pulled him from class, interviews students, called up his dad and Detectives followed him and his dad home, searched his home and he was suspended a day but got to go back to school. He had to get a psychiatric evaluation as well. Pure stupidity.
Fast forward this year, someone again says "hey you look like a school shooter". Next thing you know he is pulled out of class at the end of the day. Different students and this time he didnt say a word. Someone said hey you look like one and a girl got scared because he didn't deny it. His dad told him last year don't say anything if it happens again. Yet, girl tells admin and he again gets pulled from school. Dad comes up, detectives follow them home and again search his room. This time though it was literally caused by someone saying he looked like one. He wasn't suspended and let back to class the next day at noon after an "investigation".