If someone is only invited to a wedding for the chuppah, is one allowed to stay for the entire wedding and eat the meal?
Usually, the baal simcha will estimate some extra plates for people who do this but…is it stealing to eat the food if you weren’t technically invited?
If there are clearly designated extra seats for this purpose it would be permitted. However, by some weddings there are only sufficient seat for the invitees. Taking a seat may cause an invitee not to have a seat, and this should certainly not be done.