I have read from multiple places that this might be true and I have seen one unpowered unit dropped from around chest height to a hard floor without damage. I was thinking that it would be pretty easy to as an addon or built in from factory do a chip that powers a unit off when it's been in free fall for less time than it takes to fall 0.5-1 meter. Is there any reason why system like this has not been incorporated into handheld / headmounted units?

I buddy of mine dropped a set of anvis when trying to get it out of my helmet. The lost their power source at the helmet, hit the ground and were toast.

Sorry to hear that! Both of the tubes died?

Edit: on what surface did they fall to?

Unpowered tubes can take a massive shock and not break. Somebody makes a so called recoil proof tube which detects shock and cuts power to the tube. I think it is junk science as the shock happens so fast nothing I know of is quick enough to power it down before the damage is done.

Tubes not powered during a fall usually just break the housing. Recently I had a tube unpowered damaged from a fall but it is the only one I have ever seen do this.

Does indeed sound like junk science as the biggest G's come pretty much instantly I'd guess. If the tube had a few millimeters of damped space to move in and shut down during that movement I could see it working well. But who knows.

The thought of free fall protection came from seeing that my laptop has drivers for free fall protection and it shuts the HDD down before impact. Knowing how small accelometers of today are it shouldn't really be that much of a problem to put one in there plus a small chip to calculate the G's. When the numbers have been close to zero for some tens or hundreds of milliseconds just shut it off.

Couldn't they shut off during some rough activity when you needed them most?