This could happen anywhere. If you know that dynamically created users are in range {x} and AD/LDAP users are in range {y}, then a good sysadmin would choose a very high range for batch creations of specific types of accounts. This is fairly common practice. Modern Linux and Windows can support millions of UID's, so it is perfectly reasonable to say, "We are going to use range {y} for this project then nuke that entire range when we are done".