Part of my work in the office is inviting guests to events. Actually, I just assist the event officer in doing so. We start by sending fax invites and eventually, send formal invites either through courier or our liaison officers.
When the invites have been sent, we call up the guests to ask if they can make it to the event or not. This is when the problem arises. Most of the guests take a long time to respond. Some even don’t respond at all; they’ll just surprise you by showing up during the event proper.