Can copper be used for fuel line?

I have copper fuel line on my Duster...no problems...not to say failure is not possible, but i have worked as a mechanic for 10+ years and used alot of copper and ive never seen it break due to vibration or age...I have seen it chaffed through, but ive seen steel chaffed thorugh too...my buddy even used it for brake lines for years (yes, its a no-no according to the law) and he says hes never seen one blow