To treat every candidate he should ask the same. The recruiter should ask question according to the qualifications, knowledge and IQ of the candidate.
The task of a recruiter is not a easy task. He has to meet thousands of people daily. Each and every person is different from the other having different qualification and skills. The recruiter should not treat every person as the same.
It is generally not advised the recruiter to be harsh on the candidate. Also he should not do fake promises to the candidates to increase recruiting effectiveness. The recruiter should explain all rules and norms of the company to the candidate.