Yes, I think you're right. There is only one Certificate for each Event. There are no sign-in/outs for the Event.
At a minimum, to get a Cert for the entire Event, the Attendee must sign in and out of each Day of the Event.
However, there may be individual programs (Days or Session) for which an Attendee could get credit. These credits show up in the single Event Certificate.
In order to get credit for each program, the Attendee must sign in and out of each component of that program.
Let's say, for example, an Event is two days long. The first day is a combined session; everyone is in the same room. The second day they have breakout sessions. An Attendee signs in and out of the first day. Then they sign in to the Morning A and Afternoon B Sessions. They get a Certificate for Day 1, Morning A and Afternoon B. Someone else could get Day 1, Morning B and Afternoon A. Still another person could get Morning A only.
Or is this too complicated?