There are only two kinds of people in the world. Those with Google accounts and those without. Your calendar will either be available for view by the whole world or only by those with Google Accounts. They won't tell you that. They'll give you a "URL" as the Private Address for your calendar but that is just a page to sell the user on setting up their own Google account. Never give any corporation the contact information for your friends and family. The only purpose of a corporation is profit.