(I haven't read through all the replies to this, so I apologize if this has already been covered...)
I think that the 'shunning' bit that they do goes waaay back to the days when their main intent was to make you feel like dirt - and it was a 'control' thing, that kept you in 'isolation'.
It worked, because an individual didn't have any/many outside friends that they could talk to - especially about the JWs. (One wasn't even supposed to speak to another DFed/DAed individual). So, they tried like heck to get 'back in' to the JW organization.
Nowadays, with the Internet - it's a different ballgame. People get curious, look up 'Jehovah's Witnesses' on some search engine, and ... well, their eyes are opened a bit.
The effect of shunning is much less today than it was years ago, as a result.
The only cases where it is still half-way effective is when family is involved.
The way that their techniques are being defeated is by their methods being brought to light. By telling someone - who is not a JW - what they are doing (I.E. shunning). This makes them look like the fools that they are, for practicing such a childish thing like shunning.
Just my .02 worth... your mileage may vary... not available in all states... some restrictions may apply...
Regards,
Jim TX