Great question! No personal information from your Google calendar will never appear in your Routezilla calendar. The key for this feature is that whatever time you book out of office on your Google calendar, will automatically make that day (or days) unavailable for booking on your Routezilla schedule.
KEY POINTERS FOR THIS:
Make sure that you have the right calendar checked on the left hand side like shown here:
Be sure to set your event to Out of Office when creating on Google:
