We have a lot of User OUs that need to be scanned, and one OU that we use for service accounts that don't need to be.
Rather than having to manually add all the OUs that we need to scan and leave out the others, it would be nice if we could exclude a particular OU and add the top-level, similar to the way IP ranges or device types can be excluded.
The OU filter allows you to select which OUs you do want to scan. As mgiljum mentioned, it is not yet possible to exlude specific OUs, only an entire domain. I added this topic to the scanning exclusion improvements feature request.