From what I've read, there's about 50% misinformation here and about 50% fact. (Sorry, the spaceship one is pure fiction. Are you confusing Mormons with Scientologists, perhaps?)
There is no official "shunning" policy. That doesn't mean that some family and friends won't react with shock and horror when a Mormon leaves the fold. Sometimes this can, indeed, lead to shunning. Most of the time Mormons are told to continue to be loving to the wayward family member. It's likened to Jesus leaving the flock to find the lost sheep.
One minor thing. Someone mentioned the super friendly Mormons at Kirtland, Ohio. I suspect this has as much to do with the fact that most Mormons are Westerners, who are, in general more open and friendly with strangers than those in the East. I noticed that quite a bit when I moved from Utah to New England a couple of years ago.
BTW--thank God we were allowed to associate with nonbelievers. That sounds like the hardest thing about being JW to me. I can't imagine how I would have escaped if I hadn't been.