Geez, I have a problem getting my friends and relatives to come! Often they feel like they are imposing, but I try to explain that one of the joys of having DVC is to share it with our friends and family. Luckily, they all understand that this is something we paid for, and always try to do something for us to compensate (e.g., buying the food, rental car, sometimes even plane tickets, etc.), but I will never take staight out payment (unless I rent out when we're not with them.)
I've read several posts for people from many threads who would never consider using their points to bring someone else along (whether it be bigger or extra rooms), but I don't see it as wasting my points. I think of it as a way to enjoy my own trip more by sharing the experience with people I care about.