Anthony, the blurry picture is called camera shake! Even with dirty glasses I can see what is needed to see. I did not want to use my flash. Setting up a tripod was too much of a PITA ! Sounds like the sky is falling!
I agree that the solenoid should be placed in front of the needle valve. But not for safety reasons. I read some of the dangers about CO2 systems & feel they are not that valid. For 1, a check valve failure is not happening. Also , I have watched systems with no pressure either CO2 or air stones & the water never comes back down anyway. Is it possible, yes, but I have not seen water come back down & if it did the check valve would catch it.
If the CO2 tank leaked it would most likely leak slowly unless the tubing broke or solenoid failed which would be slow anyway because the needle valve would release the gas at slower rate than if the entire tank was outgassed! I have 1500 square feet with many house plants & central air. If there was a big leak at night & I did not feel good I would know fast in the tank area. Even if the tank leaked all out at 1 time & I was asleep it would not kill me. Too many square feet! If I stayed in the room long enough I would know the symptoms, it would not flatten me fast.
I believe you are being too critical about the solenoid position. From an aesthetic point of view it has its advantages, & yes its a little safer, & also (harder for some people to replace the solenoid as mentioned). I ran a pressurized system before this for 3 years without a problem & even bigger house, 2000 square feet with leaky windows. I never thought twice about it!
Besides, there is still a needle valve in place so the C02 would only leak out from the cylinder as fast as the needle valve would let it. All the threads on this website & not 1 mention of people being killed or got sick. You want to talk about dangerous. I think the DIY are more dangerous. I had CO2 leaking all day & night for 3 months in my tank room because the way I was running it & not once did I feel sick. Now if you have a small apartment that is under 700 square feet or less with a 20 lb tank you should take more precautions .
My 3 cents.