My understanding is that it is based on your address. My MIL lives with us and she received a 40% off PIN at our house. I called and was able to book it because we are in the same household. (I was lucky enough to receive this PIN in my name via email a few days later though, even though I didn't end up needing it.)
I was worried about the same thing, but had no problems. The CM wasn't sure (it sounded like he was new), but when I told him I thought it was based on your household, he put me on hold and when he came back he said I was right and I was able to book 2 rooms (one in my FIL's name...who is divorced from MIL) without a problem. I think he said he looked it up in a manual and verified it was based on household.
Sorry, that got long-winded, you shouldn't have a problem!