For example...
Deleting an empty dir wrote:
This directory is empty, remove dir? (can be undone, by creating the dir again)
<dir-name>
...&...
Deleting a non-empty dir wrote:
This directory is NOT EMPTY, remove dir & all its contents? (cannot be undone!)
<dir-name>
...or maybe...
Deleting a non-empty dir wrote:
This directory has <size> of data in it, remove dir & all its contents? (cannot be undone!)
<dir-name>
...<size>, for example, would say "100MB" or "100 bytes". There should be the option of disabling each confirmation separately, like allow removing an empty dir without confirmation (rmdir <dir>), but still confirm on deleting a non-empty dir (rm -r <dir>).