Hello Andreas,
Welcome to the forums! That is a very good question.
Our plugins do not integrate with Google Calendar or anything alike and event are not automatically added to any outside calendar.
When visitors to the website are viewing the details of an event, at the bottom of the event they will see two buttons, which will allow them to either 1) add the event to their google calendar (they need to login to their google account) or 2) save an iCal file which they can then open / save in their preferred calendar software / application (like Outlook).
You can check an example event or our demo site here: http://wpshindig.com/event/coffee-code/2016-06-30/
Let me know if this answers your question.
Cheers,
Andras