It is not a requirement. Consider the Oxford English definition: https://en.oxforddictionaries.com/definition/harassment https://en.oxforddictionaries.com/def

It is not a requirement. Consider the Oxford English definition: https://en.oxforddictionaries.com/definition/harassment https://en.oxforddictionaries.com/definition/harassment > Aggressive pressure or intimidation. ‘they face daily harassment and assault on the streets’ English doesn't have a definitive dictionary, anyway -- usage determines meaning. It has been the case for decades that a single quid pro quo proposal could be ruled as "harassment" in court. (As it should be!) Is it any wonder that colloquial understanding would reflect legal reality?