hey Dale I get where you are comeing from but the point of view of a professional (in another industry)I suspect you are missing key components from your post.
On a daily basis I deal with people who don't know what end of the screwdriver to use to tighten a nut and bolt.
Could they learn? In most cases YES. Most of em even figure out its not a screwdriver but a wrench you use on bolts.
The trouble is at that point in time letting them loose with spanners means things get broken.
To quote your example-they would tighten the valve so much that the thread was busted and they were up for a new reg.
So from my POV in response to your post Often it isn't about protecting my income stream so much as protecting the eejuts from themselves.
Now money where mouth is. I used to regularly run "spanner evenings" so that people could learn in a workshop environment how to "fix that hose". Check their own oil,change brake pads,etc. The simple stuff that used to be taught father to son (or daughter)
So you would ban people from fixing their cars at home? Only magical mechanics that cost over 100 an hour can touch my car? Or its only okay if a professional teaches them. So my dad shouldn't of worked on tractors and trucks with me because he isn't a journeymen mechanic. Man if only the scuba police could start helping people in all the aspects of our lives. No more unlicensed swimming lessons or water pump fixes.
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