[whpalmer4]

Well, why don't you just sync the device in question? Doing so once per week will keep that warning away. Or, if you don't plan to do that, go to the Sync preferences and delete the device until such time that you want it to be synced (though you'll lose any outstanding changes on the device if you don't sync first). I'm not sure what the point of having your data on your iPhone more than a week out of date would be...