I don't think so, but I have never gotten code so don't know what requirements are to use. I can't figure out how some people who have never been to WDW get codes either, but they are linked to specific people.
It might be worth a shot to ask, because it is your mother or sister and maybe you can use it. Do they live at same address? Anyway, I'd try for the savings.
Depends on which cm you get. Many have reported this working on these boards in the past. I got a pin code one time by calling and asking if I could use an email code a friend had given me- I had no code by my name. The nice cm gave me the rate. You never know, it's worth a try!!!