Teachers fear allegations of sex with students
It's a teacher's worst nightmare. A student either misinterprets a situation or simply makes up an incident of sexual misconduct between him or her and his or her teacher. The student may later recant his or her words. However, by the end of the ordeal, the teacher's name has been dragged through the mud. Ref. Source 7
It is more common than we think. Just recently a male teacher was found non-guilty after a teenager girl said she and the teacher had a sexual relationship. Whether is true or not, I don't know but the girl has a history of lying, she also accused another man of something similar and that man is also in jail, she also accused another teacher but then confessed it was not true so her testimony was not credible. If I was a teacher in the US, I would be afraid as well!