I’d say it does not matter if the camera is in the housing or not. As far as them only looking for professional equipment, I’m not so sure about that. On our last trip, two divers from our group were profiled and pulled aside for “inspection.” One was charged a $75 tax on a 10+ old SeaLife DC2000 camera and the other was charged $150 tax on two video lights. They took both of their passports and would not allow them to leave until the tax was paid. Video lights are not even considered taxable, and even though the diver had a copy of the law, they didn’t care.