This issue is definitely way past the date of expiration, but I love forums and spilling thoughts for folks who might stumble upon a case like this in the future. There's nothing wrong with making up your mind to NOT fulfill his request. But the best policy should always be to say the least amount possible. You are obviously not comfortable "giving in," for various reasons, and that's fine. In cases like this, hand the thing back to him WITHOUT the requested material.
"Here's your USB stick. I didn't copy the info onto it. Maybe later."If he presses you or asks why not, remain positive and frame your position.
"You seem like a guy who could be friends with me, but it didn't feel right at this point. No hard feelings, bro. Okay?"If he's pissy and presses further, just tell him he has to earn your respect. But basically if you're at this point, you've gotten all the info you need to know about about the kind of person he is. AND, you've kept your frame while he lost his.