When they use asay, it doesn't throw an error but doesn't appear to admins?
This is because the operator group had the permissions to see those, and was being inherited by the other groups. When you deleted the operator group, you removed that permission from the other groups, too. (This is why there are big warnings when you delete a group, asking if you're really sure you want to do that).
The permission string necessary to see asay's is conveniently enough, "ulx seeasay".