NFL

I think the fact that time had expired had something to do with it.

Strictly speaking they went for a two point conversion and then keeled, but given how the saints only had 8 defenders (and one was the punter) and took ages to come out to lineup they really need to bring in a rule; either the defending team forfeits the extra point after X amount of time or make it like overtime don't need to kick it if immaterial to the result.