This trick will work many times. Let your friend be normal and take it out show to TTE as usual. In 50% of cases they won't check it.
Suppose he checks then he will be considered without ticket and he will have to pay charges as usual + Rs. 200 extra.
My advice is not to tell your friend and let him carry the ID card. Otherwise TTE can figure it out from your friends face. Let him show as usual.