T***l reviewed a some 50L sacs this month. I was looking at one of the OMM sacs they reviewed and mentioned to the assistant that I had read the review in the magazine and that I had been looking for a lightweight 50L sac. He showed me a pac from Osprey that hadn't been reviewed (neither had the Jam2 for that matter) that seemed excellent and well designed. When doing comparison testing in the magazines it is very difficult to form an opinion if there are obvious omissions from the range tested.
At least the reason for omitting the Inov8 is because it didn't meet a pre-determined brief. With such an array of product available, the only way to conduct these comparisons is with a tight brief. Also, listing the manufactures in the article that didn't respond to the brief might help. Or even a list of, "You might also want to consider ..."
I assume the TGO team have to tread a delicate balance with the manufactures and distributors. I would guess that it is not financially feasible for TGO to purchase all the products that they sell - which would be the best scenario for independent review. In addition, I'm sure the manufactures see value in the promotional benefits of a product review - assuming it's positive.