Big Foot: If I recall correctly, I think I saw a photo a while back of a bunch of RMC cadets in full ceremonial #1s, complete with pillbox at a hockey game... vs. Westpoint, I think. (I think one of them had painted their face in RMC colours as well) Is this still in practice?
As for wearing of uniforms, I've seen some regimental ruck marches with combat pants and boots with Regimental t-shirt. No problems, as long as it has the permission of those in charge. I think it's pretty much common sense for anything - get permission. I know a kid who wore DEU to his grad, another wore his for a school presentation about the military, others get married in theirs. They all sent in a memo asking for permission, and it was given (with the provision of being professional while wearing it). If you're unsure about wearing something, just frikkin ask! No one expects you to know everything, and I'm sure your RSM would rather explain dress regs to you rather than having to jack you up later for mixing kit, or wearing DEU out of working hours.