I switched from another scheduling system where you have the option to turn off online booking, or keep on online booking. That way if you need to know whats going on that day at work, like someone is coming in to shadow you, people can still book online, but you know other things going on it your day on the same calendar. The time blocks were different colors (either light grey or dark grey for example) so that you know that light grey is still able to online book, and dark grey is not, that way you don't get confused.