There is nothing wrong with that. If you have doubts (reasonable suspicion) then either don't do the deal or ask them to prove they are who they say they are, of legal age, a resident of the state etc. That is sticking to the letter of the law. To ask to see that info when there is no reasonable doubt is a different story all together.I don't typically ask to see anything unless I have doubts, and it's not to copy their information, it's just for peace of mind - and so if I am ever in a position to be questioned, I can say "yeah, he was old enough and from this state".