I was referring to the external bandwidth. Even if pulling down a request takes hours, forcing them to start off peak will significantly shift the impact of the incremental demand. I'm guessing that most download requests won't be for your entire archive - someone might have multiple months of rolling backups on Glacier, but it's unlikely they'd ever retrieve more than one set at a time. And in some cases, you might only be retrieving the data for a single use or drive at a time, so it might be 1TB or less. A corporation with fiber could download that in a matter of hours or less.