Disclaimer: I'm (nowhere near) CL.
Whilst speculation, the main reasons one might receive CL:
- direct spend with QF
- control of spend with QF
- profile (corporate and public incl "celebrity")
- contracts with QF (large corporate typically in both directions, both sponsorship by QF of the member's corporate entitiy, or the corporate entity has a substantial contract with QF services)
Reasons for removal:
- substantive withdrawal or cessation of above
- program abuse / misuse
- other "misbehaviours" towards QF
I'm sure there are others in both "columns", but the above is indicative.
My understanding is there is also an attempt to keep the numbers to a reasonable limit, so whilst the above inclusion criteria may not have substantively changed on direct dollar or face value, it may apply relative to others.
I'd have thought (as a CL) your husband would be able to phone or email with a polite "I was wondering why" if the answer wasn't obvious.
Be fascinating if the OP comes back with what the "answer" is (no doubt keeping it general to protect identities)?
Edit: Interesting question in the context of this thread (may / may not be relevant to the OP's question)!
http://www.australianfrequentflyer....antas-keep-notes-their-77797.html#post1497380