Meeting invitation sent to email box should by default appear in calendar (even if the user has not responded to it). The invitation could appear with a different color suggesting user that he has not yet responded to the invitation. Displaying the invitation by default can help users to get the picture of all the invitations (Responded/ Not Responded) in the calendar, currently i miss all those invitation which i have not accepted yet. This would also ensure user gets a alarm even if the user has missed to act on the invitation.
Currently if i miss responding to a invitation i have to scan my old emails to find the invitation and act on it.
Note: I use v 6.5 (will be upgrading soon), dont know if it is already a feature in v8.