Code samples shouldn't be required. If they are, that's a -1 for the company, but since no company is perfect, this will not typically be a deciding factor.
All the code I've written is proprietary, and yet I've written good code. Also, most of it has been contributed in part by other people, too, so the "genius" you would read would not only be mine. (Which by the way, you never can tell, when you get code samples from other candidates.) I can't provide samples, and I'm not going to do it: it would be crazy for me to publish company owned code for you to read it. You'll have to trust me.
IF you the company can't understand that some code is not my property, and still require it, then it's an unfortunate situation, because you won't have me as one of the candidates - and I don't know if I'm the best one, but I'm sure I'm a good one.
And no I don't code for a hobby, because 40 hours a week is enough for me.
PS - You can also ask them for clarification if you really want to know what they want. Companies are not all the same.