Conerns/objections to having a 3D printer in the classroom?

Hello everyone,

I am looking to build and donate a 3D printer to a local elementary school. I've been working with the principal and we'd like to get some feedback from others who have 3D printers in their schools:

1) As a teacher, how do you use 3D printers in your classroom? How does it help your students?
2) For those with 3D printers in your classrooms, did you face any objections or concerns? How did you handle them?
3) As a parent, what sort of questions/concerns would you have about a 3D printer in your child's school, if any?
4) Anything else we should know?

We really want to bring this technology to the students, so any assistance would help make this happen. :)