Yes, they should.
Not only are they still students and attend classes, but they aren't doctors because they haven't yet earned a medical degree (MD or DO). They are still under professors, and still earn grades.
I know of no profession that doesn't charge students tuition during university-supervised clinicals; not nursing, not dentistry, not rehab professionals (PT, OT, speech pathology, audiology, neuropsychology, etc), not techs (x-ray, lab), OR medical students.