>There is also a concern of what happens with all the info they DO find on the phone. If he has 100 contacts in his phone, you know that all those 100 people are going to be looked at even have they have nothing to do with what happened.. Now you've got the feds on a 'fishing expedition' - which can quickly turn into a 'witch hunt'.

The only difference in witch hunt will be those on the contact list but not contacted by any means - connection info will be available for some time into the past even without calling for NSA backups ;-)