In general your Sync.ME profile (ME Card) will be updated with details from your public profiles. For instance, if your Sync.ME profile is synced with your Facebook account, the Sync.ME profile will get the info from your public profile on Facebook.
While in profile edit mode, if you press "delete" to the location and then press "done", the location will come back from Facebook (even if overwrite is off because it is a blank field and the field comes from the social network).
The only way to edit this is to manually type another location in the field. Then press "done". Once it is manually changed, the app should not overwrite this.