We can customize downloads by the number of days. We need to be able to customize downloads by the hour as well.
Marynelle Chew commented
While I did turn off downloads for particular titles with limited users, many of our students live in countries where the internet is expensive and not stable. I'm sure students in the US face similar difficulties. It would be helpful to our students if they could read offline for a couple of hours--no one will read much longer than that--and helpful to their classmates if the download were shorter instead of keeping a title unavailable for an entire day.