Should I act as referee for my students?

It is important that

It is important that references are honest and yet also helpful to the candidate so you need to make sure that you do not devalue yours by providing them for every pupil. So they should be given sparingly and you can encourage pupils to go to the teacher of the subject they excel in or to organisers of sports teams or other interests.

no way

no way

I would say yes. Be honest

I would say yes. Be honest but let your students know this isnt a 'free pass' and that you will be truthful in your response.