I, like a whole bunch of people in the photography community, have several external disks permanently attached to our Macs. That's goood....
The problem is that when we chose Ingest Disk then all those disks pops up as disks to ingests in the Ingest widget. It really should be possibly to permanently block disks from the import dialog so that the erase and unmount when finished options can be used.
You might not wanna have your home folder erased and unmounted you know... ;-/