I don'think I could do that with my dayjob calendar (even if I wanted to), as we're on Microsoft Office 365 and I'm pretty sure it's all locked down so I couldn't. It does raise eyebrows that I make my calendar public within the organisation, though. Obviously a few meetings get labelled "private" and things related to supersecret projects are referred to by codename, but almost every appointment in my calendar is public to anyone in any of our offices. I find it quite curious that so many colleagues find this surprising.