Apologies if this is common knowledge, but my guess is that you won't have tried it...
Many of the Schools that I work with here in the UK struggle with things like webDAV and indeed many schools don't provide email addresses for their learners. Tools like Dropbox are often for political reasons also a problem.
So accessing work created by students on "class sets" of iOS devices (as opposed to 1:1 ownership) can be problematic.
In my workshops I will show schools how to save via USB file sharing in iTunes, and recently discovered that all the teacher's laptop/desktops can be set up to access a class set of iPads wirelessly. Sure we can do this as consumers on the devices we manage, but it also works wirelessly with devices that our computers are not managing.
Teachers can access files wirelessly whilst the students are working without disruption.
This means that files can be assessed and saved back to the devices, even if they are being used by another group of learners, provided they are on the same network as the teacher's computer.
The crucial thing here is that it doesn't have to be via the computer that manages the devices.
I've blogged about here....