As someone who has just finished working with a Guide Dog from GDB as a senior in high school, I thought I'd comment on the current discussion about having a dog/puppy in high school. Obviously, I know very little to nothing about puppy-raising, other than that Julio's puppy-raisers are amazing and did a great job. But with that in mind, I think I can comment on the issues that might make the school principal reluctant to allow a dog in high school.
First, the distraction factor: To students in a high school, there's nothing that can't be used as a distraction. But the dog does not have to detract from the classroom environment. In fact, the dog is often a help in classroom exercises as well as a learning experience for all students. On the first day of school, many of the teachers explained Guide Dog etiquette. They were provided with this information by me in the form of a five minute presentation and the brochures GDB provides. Teachers usually don't have a problem squeezing in some short information during their first-day-of-school lectures. Often, if I was in the class, the teachers had me present the information and opened it up for questions, but that wasn't a requirement, and most students just asked me after class anyway.
Most of the time, students forgot Julio was there. He generally lay quietly beside my desk and often slept through the lecture. Yes, he did occasionally snap at a fly, but very few students noticed, and quite frankly, those students were not paying attention to the lecture before he snapped. Once, later in the year, Julio threw up. This did cause a minor disturbance, but any student could have done the same thing with just as much disturbance.
Now for the ways Julio added to the lectures. In French, Julio was often used in the examples the teacher used, explaining that "Il dort", "he sleeps", or something similar. In a law class, I was able to help others understand more about the Americans With Disabilities Act and Guide Dog laws. Much of Guide Dog work can be compared to psychology, and I made the connection verbally a few times in class.
Students learned more about disability awareness. They learned about Guide Dog etiquette. Both of these skills are very important for students to have under their belt.
Relief issues: I only had to leave class once to relieve Julio. Let's just say he was a bit fragrent. But that wasn't a problem, since students are allowed to take bathroom breaks, and I was able to leave with no more disruption than if I had asked to use the rest room myself. Since I pick up after my dog, their was no extra hardship to the custodians (accept for cleaning up the afford mentioned vomit).
Lunch rooms: I can't think of something more difficult for me than a high school lunch room. There is a ton of food on the floor. But, this is all the more reason for a puppy-raiser to take the dog there (when the dog is ready). A distracting environment like that will help the puppy learn to ignore food. If the dog is not ready or the handler feels it is appropriate, the dog can be put in a crate or on tie-down. I just used the room where my printer, Braille embosser and materials were kept. A raiser wouldn't have access to that room necessarily, but other arrangements could be made.
Allergies: I never had a complaint about others having allergies to my dog. I know there were people in the school who had such problems, but I kept Julio well-groomed and never heard a concern. If a student did have a problem, seating arrangements can be made so that the effect would not be strong, if it even occurred.
Over all, I would say that I had a very positive experience with Julio accompanying me through my senior year of high school. Like any new Guide Dog team, we had our struggles, but I don't think they were greater for me because I was in high school.
It's important that the school be willing and that the student be mature. Without knowing specifics, I can't say "yes, this will work!". But I hope this message clears up a few things and hope that it can be helpful for the students in question!