When I was 7, my eldest sister got married. Somehow on leaving the church I decided to help guests find the buses to take them to the reception. I was a helpful, if slightly bossy, child. While I was doing that there were the various pictures taken at the church, and then the official cars took my family to the reception. I got there on one of the buses.
At the hall for the reception, more photos were taken of the families and I mingled with the guests.. Eventually the guests were allowed into the main hall and the reception carried on. It was only when the photos were seen that my family realised that I hadn't been present with them from the time of exiting the church to the guests getting into the reception, a period of about an hour.
These things happen, as per David Cameron's mistake. This resulted in tragedy here and using it incorrectly as deliberate to indulge in some petty points scoring against Christians is distasteful.