Barbara Harrison's book goes into great detail on the effects of the various degrees of 'shunning'; the best thing to do with her book is to cut and paste the chapters one by one into one big word file and then you can 'search' for things. The same is true of a lot of books like these.
Watchtower admits that the whole idea behind marking, reproving, and full-fledged 'shunning' is shame and 'protection from uncleaness'. (translation, more shame). JW's are really under the impression that expulsion/shunning never takes place without good reason (gag).