Don, the Kona is made out of a thick plastic material with beefy vice-grip top seal, unlike those ziplock bag ones that are rated for 60' deep. I bought one of those thin plastic ziplock bag one ($2.95 from eBay), compare it with Kona pouch & have similar thought that ziplock bag one is probably only good for snorkeling. So hold your horses until I test this Kona pouch. I plan to put a folded paper towel inside the pouch, put the pouch in my BCD pocket, take it down to 100'+ deep & check whether the paper towel is wet by the time I get back on the boat.
Based on what I learnt from physics, even if some water leak into the pouch during an hour dive, as long as the pouch is not completely flooded with seawater, leaving some air still trapped inside the pouch, due to the trapped air inside the pouch being compressible, the pressure inside the pouch would not reach 22.4 psig (50' water column equivalent pressure, which is the water column pressure rating for the PLB1), then the PLB1 would still be OK. Of course, a complete dry inside pouch is preferable. We'll see in a month, when I go diving & testing the pouch.