Rick entered a date on his calendar on the iPhone via FantastiCal, and his friend noticed that it appears on his calendar as well. Leo says it will do that if he had set it up that way. The calendar will see that he's put a name in the event and email it as an invitation. It's a nice feature, but scary if he doesn't see it coming.
Rick wants to know where this default behavior is coming from, his iPhone or his Mac. He'll have to go into the settings and disable the invitation option. He may need to also go into iCloud settings or the settings for iOS.