Well it depends on what default checks the cmk have and the ones developed by you (colleague/company/etc).
If you hadn’t it configured this way, maybe you had some custom checks developed that were in use.
EDIT: Yes I’ve seen what you are saying. It should be detected automatically by check_mk once you do the full scan. It shouldn’t be needed to create any rule for that. Strange
Have the IDRAC been updated meanwhile for instance?