So this intermingling of Gmail and Outlook contacts reminds me of WinPho and Facebook. When the windows phone was first released if you synchronized your Facebook account with your windows phone your contacts app was filled with your Facebook contacts. I attended a demo of the Windows Phone where this was pushed as a cool feature and something they thought was fairly unique proud of as a result. Think it used Facebook Connect to do this. So spotty teenager steps forward and says that he's done it and now wants to undo it as it's driving him mad. He had nearly 200 friends on Facebook none of whom had their contact details visible and therefore in the contact app he had nearly 200 empty entries. He also had a fair few of these people listed twice as a result, once with details once without.
Asks how to delete the Facebook empty ones and is shown a method to do this which he dislikes. That apparently only hid them not deleted them (they turned up if you searched) so is given another suggestion, unfriend them on Facebook and then ask to be their friend again. This also appears to be as popular as a dose of the clap and the young gentleman suggests with a few four letter words interspersed that his new phone will be wiped and returned to the carrier.