With all the BRC classes close to me full, I'm going to try to walk in to one of the Columbus/Broad Street classes. I saw a couple of posts by people who took a MSF class as a walk-in, but I'm wondering: 1. Is it common or uncommon to make it into a class as a walk-in? 2. Would arriving 30 minutes before a class to get on the walk-in list generally be early enough? Thanks for the insight.