Apple has posted a Knowledge Base article indicating that. when Microsoft Outlook is configured for non-cached Exchange mode, syncing your Outlook Contacts to iPhone or iPod touch can result in only ...
Echoing some of the guidance in our special report on troubleshooting iPhone sync problems, Apple recommends that isolating problematic contacts can resolve an issue where: "When attempting to sync, ...
If they're running iPhone OS 3.0+ then they have the option of deleting contacts off the phone, or keeping them on the phone.