We deal with the issues brought up by others that most developers can't really do this, by asking them to bring a piece of public code that they like and give 10 minute presentation about it.

The code that they select tells a lot and is a great starter for further discussion and finding out about how they think. It also demonstrates an essential skill, and that is evaluating other peoples work and how to work with it rather than against it.

I work in an industry that would fire then sue me for taking samples of my actual work.

Many would reply with open source or personal projects, but I will head that off by saying that not everyone does open source (for some people, 50 hours programming a week is all they want to spend) and there are many who do open source in other areas and perhaps not with the same level of professionalism and expertise.

And others of us would be in jail.