I used to jump in and then swim back, but for the past 18 months (apx 6+dives a month) I've just held on to it as SSR describes...
Giant Stride entry, hold camera with bent arm above my head. The fins break the initial shock and the bent arm absorbs the next shock... and the gently hits the water... I used to worry about it, but then driving back and forth to dive sites, I figure the camera set up is getting worse shocks (even though I carry it normally in a milk crate lined with bubble wrap) driving around and nothing shows any different wear and tear.
From the above instances, it would appear to be a problem whether you held it or picked it up... Now if I were doing a GS off a 5 foot deck, I'd think twice, but normally not any more... Oly 4040 in Tetra housing with 2 SB105 Stobes...
I love the camera and set up as much as other divers love theirs, but I'm of the thinking that these things are not as delicate as some make them out to be. You set them down gently with about as much force as I go in the water... Now would I drop them on the floor, absolutely not.. but then I don't carry them around on a feathered pillow either..
Have had the camera ever since the new OLY 3030 and 4040 came out, same strobes too..
Night, doesn't make any difference as you have the dive light secured... heheh.. have a scare on my forehead from doing a back roll with a dive light NOT secured...
Haven't tried a back roll with the camera... yet.... that is.. but close to chest and all bundled up, would feel comfortable in doing it..
Just my $.02 worth.