Last Updated Dec 5, 2010 11:44 PM EST
That's a thing of the past. Effective right now, when you schedule a meeting in Google Calendar, you'll see this:
Click the link to Make some attendees optional, and you can click the icon next to non-essential or info-only attendees to reflect their status. Now, when those folks get their invite, it will be easy for them to know that they only need to attend if they really like meetings.