I would like to get some real facts about the risks associated with jumping in to the water off a dive boat with the camera housing in the hand. Some people say that they always do it that way. Some books and manufacturers instruction manuals warn against it. Here on wetpixel there must be enough underwater photographers and videographers to get a reasonable statistical analysis of whether the risk is real or not.
If you answer the second question with "but it leaked", maybe you can provide some more information. Was this your first dive with this housing? Was this recent event with a modern housing or 30 years with a home-made housing? Had this housing ever leaked before?
Of course, to make the results meaningful, please restrict yourself to your personal experience.
Regards
Peter