Even with a school that normally had a book fee, I'd still object to the iPad for every student. I did a bit of looking around for discussions of this sort of thing.
- Not all textbooks are in eBook form. So a student will have to have an iPad and a bunch of textbooks. Then there's the licensing fees for the textbooks - if students normally pay for the books, then it will likely be an iPad + licensing/purchase fees for all the books on it.
- It drastically increases screen time for kids, and reading on a screen can be physically fatiguing - headaches, eye strain, etc. Personally, I can read books for hours on end with no problem, but if I'm concentrating hard on a screen for too long time I get dry scratchy eyes and have to stop for the day, even if I still have work to do.
- iPads are expensive and both easily broken and a hot theft item. Kids tend to be careless. Insurance tend to be either quite expensive, or very limited. I suspect they might have a hard time getting an insurance company to provide group coverage for a bunch of 14 year olds who will be carting around $500 items that break if you drop them - and they will be carted around pretty constantly.
- You will need to spend even more money on peripherals. At a minimum, you'll need a case/screen protector and a couple of styluses (again, teens, lose things easily).
- iPads are not specifically a text book reader. They also play games, do email, web-surf, do Twitter and Facebook, etc. So you're giving kids email/web/game machines to carry around with them constantly. That's not going to result in kids spending more time on 'fun' educational games and reading textbooks so much as a lot more Angry Birds (They've found this with programs providing computers to low income students - a lot more game playing, not so much increase in school performance).
If they cripple the iPad's functionality (turn off internet, block games, etc) I can see parents being legitimately angry at having to pay full price for a broken tablet.
The nook makes more sense for a lot of these things - it's sturdier, uses e-ink (which makes a big difference for readability), is much cheaper, and is a dedicated ebook reader. However, textbooks are not well suited to the small screen format - it would work fine for novels, or straight text, but if you've got equations or illustrations in there, it becomes pretty unwieldy.