Just returned from Bonaire where a fellow on the boat had the Backscatter system. According to him the vacuum caused a problem with his camera in that not all the buttons worked. His theory is that the vacuum caused the buttons in the camera to get sucked in a little bit which meant they did not meet up properly with the housing controls. Any comments on this?
I was actually on the boat the same day he was experiencing the sticky button on his housing. I won't get into which housing it was but I will tell you that in my assessment, the button that toggles between video and photo mode was getting stuck in the down position, causing the camera to be locked up. I experienced the same issue before with the same brand of housing last summer where I had pressed the "video/photo" button a little too hard and it would stay stuck in the down position. (In my situation last summer, we repaired this issue in the field by opening the hole in the delrin bracket of the button for the metal part of the button to have more breathing room. I didn't have any issues with the button for the rest of the trip.)
Regarding the guy at the Shootout who had a stuck button and thought it was related to the airlock, I told him to talk with the housing rep (who was on-site) at the Shootout to get the button swapped/repaired.
In my opinion the issue was not with the airlock but with the button on the housing itself.