Calendar settings - don't think this is possible but I figured I'd ask

[Matthew Weiner]

I'm dealing with a lot of calendar spam lately, where people instead of just sending the phishing link in the email is sending it as a calendar invite that by default will land on users' calendars.  I'm dealing with it via the typical tools but it seems like Google's spam prevention is not as adept at handling this kind of content yet.  

To avoid that I've found some recommendations to change the settings in Google Calendar to only auto accept calender entries from known users.  

Is there a way to programatically change that option or are we dependent on users doing that for themselves?  I have a lot of users and I'll be diplomatic and say there are quite a few that would require assistance to change those options.

From the wiki I don't think so, but I figured I'd ask in case there's something I'm missing.