The sealed-until-later reveal is not a wedding-only idea. A birthday works just as well: let friends and family shoot and write throughout the day, then open it all together at an agreed moment.
Why a reveal lands harder
On the day itself, the birthday person sees almost none of what everyone shot and wrote. Collecting it and revealing it at once turns it into a present from the whole room.
The best frames usually happen in the corner you were not looking at.
Scan and shoot, so grandparents and kids join in just as easily — and it all becomes one roll belonging to that birthday.