kind of odd to call it low 02 if theres no validity to the claim....
But the use of metabisulfite has been shown, empirically, to scavenge Oxygen by multiple sources. Some of whom you seem to scorn and others, like Brulosophy, whom I'm sure you respect.
You don't require evidence of combustion every time to know that putting gas in your car makes it go vroom vroom, do you?
meta is an antioxidant, no argument from me about that. I just wish y'all would be as critical about claims of 02 success as you are with failures. If your only markers for o2 success are that the brewer likes it, then your method is a self fulfilling prophecy. You like it, you did it right, you don't, you did it wrong. Without verifying that DO was in fact low, why are you so quick to congratulate the successful brewer while questioning a naysayer?
It's a valid point. We assume that people with good brewing practices that are making good beers, and who subsequently integrate antioxidants and mechanically limit ingress, and seem to enjoy the product, are experiencing low levels of DO. Without an actual measurement there is no way to truly know. All we can assume, knowing what we know about the scavenging power, is that if people have sound general practices, that they SHOULD have success.
We also see a lot of people choosing to brew a beer they know very well as their first Low Oxygen beer. This helps people to pick out any differences, subjectively. Ultimately, sulfite strips can give you a general idea of consumption.
As far as failures, typically the ones reported don't have a fair amount of data associated. The Brulosophy experiment was an outlier and had a great write up so it was ripe for analysis and criticism. Natebrews has posted extensively on our site about his perceived lack of success and gave much data to try and elicit some troubleshooting.
Ultimately we encourage trial and error and troubleshooting. We don't assume anyone did anything explicitly wrong. Given the number of people who have, at least subjectively, shown great results, we assume that if the brewer was unhappy with the results given what he's read about the techniques, that there is room for improvement.
Failure is not a dirty word. You can fail to capture the desired results with a written procedure. You just have to troubleshoot and move on from there. We don't typically scrutinize people who are having success, because we assume that they are brewing a recipe they are comfortable with and really do feel like they are making a better beer.