If there was a definitively way to prove it one way or the other I would wager some serious cash that 99.9 % of the "it didn't open" stories are utter horse ###t or at the very least there are extenuating circumstances being left out of the story. For example, I encountered one guy online once that complained his mech heads were failing to open. After talking to him for a while it came to light that he had been shooting them into his target over and over again with the same blades and they had eventually started not opening. Well gee, no s### Sherlock.
Some questions to the guys reporting such issues.
Do you check your mech heads to see how easily the blades deploy before you shoot them? Hell, I check fixed heads over thoroughly to see that they are assembled properly and that the blades are sharp before they go in my quiver. I do the same with mech heads with the added step of working the blades. If you can easily open the blades with your fingers then it defies logic that they would fail to open on the target/deer.
Are you aware that a mech head that you shoot through a block style target will slam back shut if the head makes it out the back side of the target due to the deceleration of the arrow slamming to a rapid halt? It will also close when you pull it out of something like the target or the ground.
For those who claim to have lost a deer due to the failure of blades to deploy, if you didn't find the deer then how do you know? Also, a shot through the lungs will kill the hell out of a deer regardless of whether the blades open or not. Collapsed lungs are collapsed lungs irregardless of the shape of the hole.
I am not a huge Rage fan. I think the blades are often too wide for the power level of the average persons bow. But that said, they have some of the easiest deploying blades of any design out there. In fact the knock some people have on them is that they deploy "TOO" easy. Odd to hear people claiming that they don't open at all.