Actually, the CM discount is available to family members of the CM. For example, my brother works for ABC (a Disney owned company). Thus, he is eligible for a CM discount (though he gets a 15% discount as an employee of an affiliate company. CMs working directly for WDW get 25%, I believe).
In any case, when I went to purchase
DVC, all I needed to do was have my brother fax a copy of his ABC employee id to my guide, and I was able to purchase using his discount. His name is nowhere on my contract (neither as purchaser nor as an associate member or anything) and is in no way affiliated with my membership.
The rule that the above poster mentioned (about having to sign something saying we will not sell the contract) is actually a new policy. My guide just informed me about it when I was talking with her about an AKV add-on. Apparently, someone somewhere figured that they could purchase with the CM discount and then flip it to sell for a profit on the resale market. You now have to sign paperwork saying that you will not do this. If you are caught doing it, then the CM whose name you used to purchase is jeopardy of losing his/her job....they are taking it seriously.
Hope this helps.