If I create my own url shortcut to a website and put it on my own calendar
entry, I should be able to unblock it. This is not even a shared item, but
something I created and know is safe. Why should I have to type a full url
that gets me to the same place as if I dragged a shortcut from my desktop!
Protecting me is one thing, but I should be able to override that blocking on
individual entries if I so choose.

Even after typing the url in my calendar entry, I can not remove the
attachment of the shortcut, so I have to put up with stupid unsafe message
every time I save the same calendar entry.