Ok, I admit it, I am stingy with my points also. Actually, at this point, the only people even aware that we own DVC are just DH and I. (No flames please.) This is for two reasons - 1) we are verrrry private about our financial decisions and 2) it would cause a world of issues on both sides of our family.
My DMIL owns 12, yes 12, weeks in another timeshare in Orlando that we have no interest in. She is very proud of her purchase and sees it as a legacy for her kids and grandkids. She would be extremely hurt that we chose to purchase elsewhere. We have learned on several occasions that we and DBIL do NOT travel well together as well.
Family pettiness on my side would make it a nightmare of "you invited them but not us" or "you invited them first you must love them the most." It is just not worth going there. We purchased enough points to stay in a 1-BR for a week each year, so there is not a whole lot to share anyways.
Now, I may repent and invite someone in the future, but for now I am enjoying every point that I can use.
Again. Nothing wrong with that. If taking family causes problems or hinders your enjoyment then don't take them. I have family I would never dream of taking. My father's new wife is a very rude and crude person that I would strangle if I had to be exposed to her for extended periods of time.