the poison pill "insurance" idea is clever, but does assange really expect anyone to be deterred by it? everyone expects wikileaks to release that stuff eventually if the organization doesn't get shut down. in fact, it has already all but openly announced its intent to release the bank of america files if it doesn't get put out of business.
the bottom line is that the contents of the "insurance" file are going to be released whether wikileaks continues to operate or not. there's no practical way to stop that stuff from coming out at this point. in that sense, the contents are already out of the pen. but the powers-that-be still have every incentive to shut wikileaks down to prevent it from getting more secret information in the future that it will later release.
the insurance file make look like it could get wikileaks' enemies to back off. but ultimately it isn't a sufficient deterrent to get assange and his organization out of this mess.