Before the day of an event, I make sure the event is live in my calendar - this way it appears in the app for the rep to see. We give our reps access to the Marketo app for a week following their event, in case they need to go back in and look at metrics. However, if the event is only live for one day in my calendar, will it still appear after the fact in the Marketo app? I'm just concerned they'll go in after the event, only to find that the event has disappeared.
The Marketo Event App only displays an event in a 7 day window.
If your team needs data, they should use a report from Marketo or SFDC.