You have obviously never encountered a situation where the volt stick did not show live, but the neon DID.
I would NEVER trust a non contact device to prove dead. They can (to some extent) prove live and the non contact way they work can check a cable (again with limitations) before you cut it.
Use a proper meter to REALLY prove dead.
I am still waiting for someone to show me a real world example of where harm was actually done to someone using a neon screwdriver. People seem to worry about the microamps that flow through you and talk about the risk of component failure within them making them lethal, but I have never seen an example of this actually happening.
I don't fully trust any device such as the above, either voltsick or neon, however for the amateur who insists on poking about I think the voltstick is safer, no chance of trying to poke into a terminal and bridging a live and earth. I knew an electrician some years ago who got a nasty belt off a neon, his apprentice had dropped it into a sink full of water then dried it out with a tea towel. Obviously the newer ones are sealed to prevent that happening, neon screwdrivers are handy for proving polarity on a tncs system, in fact they are probably the only way due to not having a separate earth to reference to. I still use a Drummond test lamp and a proving unit most of the time but I do find uses for a voltstick, it's just a handy thing to keep in your top pocket for a quick test, bit like those socket testers that do earth loop tests, you'd never rely on one for a proper test however they are handy when doing a walk round, if you get a reading you're not happy with then out comes the loop tester.
I've found issues on circuits before now when I wasn't actually looking for them, a lot of the gear these days isn't intended to do a full job, just to give you an idea there may be a problem, it's how you use it that matters. A certain large organisation uses a type of loop tester that uses lights instead of a meter, green light meaning good earth is between W and X ohms, amber meaning check and is between X and Y ohms and red meaning poor or no earth is above Y ohms. now the value between W and X can be beyond the limits for certain breakers and imo shouldn't be used as a definitive test, which is what this firm are using them for, however if say you had a caretaker checking sockets in a building between inspections then such a device would be useful, no values to remember, if it lights anything other than green then get the electrician in.
I remember years ago in my apprentice days, back then loop testers were few and far between, rcd testers unheard of, we'd done some work and the old spark was testing a bond to a metal sink top, he took his Drummond test lamp and inserted one probe into the live on a socket, the other went on the metal sink, it lit. Now while this would almost certainly be frowned on today, back in the day it did prove earth.
