I really like this strategy. After one god awful experience at a company that led me to quitting after 3 months, I will not work for a company that doesn't show me a snippet of their own code. The whole experience at that terrible job could have been avoided if I could see their coding practices: early returns, gotos everywhere in C++, 7(!) different languages that compile into one >1GB executable over the course of an hour. They only did white boarding questions which told them a lot about me, but told me nothing about them.

I've had 4ish interviews since that job, and all of them gave an on-the-spot code reading assignment to walk through their code to find the bugs. It let me see who has old style coding standards, who takes advantage of modern C++ utilities, and that the interviewers are competent enough to walk through coding examples, too.