Would be great to have the option to enable and disable individual scheduled discovery scans.
You may have network maintenance on a certain subnet and wish to stop discovery of that subnet during the maintenance window, but keep scanning all other networks as usual.
You may want to stop discovery of a certain ip-range (scheduled) to identify root cause issues that has been observerd in that network, but keep other scanning as regular.
I am sure there are many more good reasons for this feature
EDIT: Marked this idea as Delivered. It is now available in ADDM V10: BMC Atrium Discovery Community | ADDM 10 | Scanning IP addresses or ranges along with many other great features.