It goes without saying that we appear to disagree. We each recognize and accept that, I assume. I see no harm in disagreeing, and I also see no need to run from it. A good debate can bring interesting information to light and improve one's understanding of a topic. Given your long and numerous posts, it seems that, like me, you are interested in this topic. The decision to participate is yours.
"Your comments about the bags being the same material, with some just thicker, are not supported by any evidence."
Debating things that are obvious isn't interesting to me. Please just read the Loksak website. They explain that Opsaks are made of polyethylene, including this sentence: “These resealable, washable, polyethylene bags are watertight, airtight, and odorproof, so they prevent animals from sniffing out your edibles and toiletries." There are, as you say, many different kinds of plastics. But commonplace ziplock food storage bags are polyethylene, and they are clearly thinner than Opsaks. This is common knowledge and easy information to find.
"As for Ari's dogs, I read the article carefully, and did not see documented the rigorous pretesting that you refer to. He says it was a concern, but very little about what was done about it. As earlier noted, those lockers could have had any number of things in them at an earlier time..."
I think this criticism of yours seem poorly thought out. In the article about the locker room study is this sentence: "Prior to beginning, one dog and handler team conducted a locker-room search to rule out the possibility of drugs on site that were not part of the study." So, any pre-existing odor that might throw the dogs off would have been identified before the test. However, drug sniffing dogs are specifically trained to overlook all non-drug odors. People commonly attempt to use other odors to conceal stashes of drugs, and the dogs are trained to not be distracted by those. The dogs were only looking for the odor of the material in the test bags, which is ideal for testing the odorproofness of the bags. Also, you have to choose between complaining that this test had too many complicating circumstantial factors and complaining that the circumstances of the test didn't have enough realistic complexity. Wild animals seeking food are surrounded by lots of other odors, too. And, like the drug dogs, the odor they are trying to pick out from the background odors is the odor of the stuff in the bag.
There are a few points that are obvious. This information is available from many sources online and I'm not interested in debating it:
1. Opsaks are made of polyethylene
2. Polyethylene is an abysmal odor-barrier material compared to nylon, metallized plastics, and foil.
3. In some industries it is crucial to have effective odor barrier materials. Companies in those industries don't use polyethylene because, compared to other materials, it isn't an effective odor barrier.
4. Real barrier bags are cheaper than Opsaks but similar in weight.
This is all we need to know. If you doubt any of these, please just look them up.
This in no way means that anyone using Opsaks should replace them. As your test results suggest, they are better than nothing. And your food cache experience shows that, for you, they work well enough. I think anyone who is using Opsaks now, and having good results, should continue to use them and not worry about this topic.
This is my only claim: if one is considering acquiring an odor barrier bag, it doesn't seem to make sense to consider Opsaks, because real barrier bags are cheaper, similar in weight, and made of materials that are better barriers. If you disagree with this statement, you are welcome to explain why.