Consider the Betty Hiner "There are no trout(s) in South Dakota" gambit with regard t stringers and cameras. Betty is attempting to employ a part of the "blue line" ethos on an epic scale. You know the deal. "There are no fish in this stream. I only fish here to enjoy the scenery. Trying to catch fish here is a waste of your time." And for extreme cases there is the, "and besides, the moonshiner/pot grower//meth brewer in the cabin beside the stream shoots all strangers." There's just enough chance of that being true to dissuade a lot of folks.
I double bag, usually with Ziploc freezer bags, my wallet, and cell phone. My camera is guaranteed to a water depth of 10 feet. Ziploc freezer bags are tougher than their sandwich bags.