I agree - I didn't like the promises that were made and not met, however my assumption is that it was the same situation as all the others "Look, our reception didn't drop at all from our normal 5 bar situation". Unfortunately, 5 bars are a dream for many of us...I routinely have 1 - 3 in my house, and sometimes even less in NYC (though that seems to have gotten better lately) - it's there that the drop is both significant and visible. My guess is that all the testing they do is under ideal circumstances.
As for what I'd expect alumacase to say...I'm not sure. Atomic and Element have both confessed that their cases cause reception issues for "some users" - while that has not been quantified as least they are acknowledging that its the case causing an issue - albeit one related to the reception area.
The bolded part of your statement I think is probably the case with most of these manufacturers. I even had ExoVault tell me that they thought that was more than likely the case with their product...that they need some "real world" testing with their cases in various locations, because where they are located (and do their "testing"), they have very strong reception all the time. It seems that most of these case manufacturers are located in or very near major cities, and those usually have strong signal, compared to some of us out in rural areas.