Depends how the student hosting is set up. The couple times I stayed with a student host, I arranged it myself. In one instance, it was directed by the school (they gave you the information for several of the hosts, you contacted them yourself), and the students had an extra mattress that they threw on the floor for you to sleep on. In the other, it was on my own (through SDN, actually), and I slept on the couch in this girl's living room.
Student hosting is completely optional; I've also stayed at friend's houses and in a hotel when going to interview.