It's a compilation of all the different areas that most protocol offices deal with. For example, Mary mentioned the orders of address, how to send a letter to Buckingham Palace, if you're asked to do that, the order of flags at ceremonies and state funerals, and all that kind of stuff. It's a very good set of guidelines. They aren't hard and fast rules; they're really guidelines.
On your earlier point about maintaining respect or reflecting what's going on, when somebody tells me there is precedent for this because it was done this way last year or the year before, my simple answer is that doesn't mean it was done right; that just means it was done before. So you have to take things in balance. That's why the general demeanour of most of us in this profession is to have quite an even keel. If we didn't have that we'd be jumping out of our windows half the time at 4 o'clock in the afternoon.
Things have happened in the past that people expect because they were cultural things, and so on. They may have just happened that way and were never right from day one. Our job is to catch them where we can, tweak them a bit, and maybe change them.