Counter-Terrorism and Border Security Bill

Like my right hon. Friend the Member for Normanton, Pontefract and Castleford (Yvette Cooper), I support many of these measures, but why is it three times? I accept the definition in terms of academic research, a journalist or the case of the Home Affairs Committee, but what happens, for example, if a teenager or someone with mental health problems watches a video more than three times? Do they automatically fall into this category, or does the reasonableness test apply?