The video in my previous post speaks to me, because of the lessons I learned.
I got my 1st Daisy for my 4th birthday (may have been christmas). That same night cocking that BB gun holding the stock with my left-hand with cocking lever in my right-hand, the cocking lever slipped from my right-hand near the top of the stroke. The pain I felt on the knuckle of my left-thumb as that lever struck me opening a triangular flap of skin was intense. Little could I know this was but a first-hand lesson, followed shortly with what getting your first stitches feels like ... :-O
Did my parents take away that BB gun ..., NO. They could see it was punishment enough that I could not cock it with a bandaged hand, and therefore could not use it. It was not even "taken away" at that point. It's not like I did anything bad/wrong, and needed a spanking. I instead learned to cock it by placing the butt of the stock behind my right knee, pulling the barrel to my chest with my left forearm, and cocking the lever with my right hand (barrel barrel naturally moved to between my left bicep and shoulder during cocking action).
Boy o Boy my Mom was pissed when she realized I'd been shooting that thing with stitches, because she thought "I'd learned my lesson". She said "your father will deal with you when he get's home". OMG, the anticipation was worse than the stitches ... Dad get's home, I am called into the living room, my precious Daisy leaning against the couch. Dad is like no-way, I don't believe it. Says show me how you could cock that thing in your condition ... They both looked at each other, my guess they understood the creativity illustrated something significant. Additionally, they had felt the pain I had experienced as only parent can when their children are injured.
As in the video above, I too learned about reflective energy (the metal sign as a backstop and the use of steel BB's).
Partial list of lessons here:
Energy & Recoil (day one, scar to this day to prove it)
Reflection of energy (BB ricochet, yep been hit in the face just like the video)
Energy absorption (steel BB vs lead pellet and/or lead BB)
I could go on with the lesson of my youth from both that first Daisy BB gun and my first knife Old Timer Stockman (5th birthday, along with Arkansa stone and hand written diagrams from my older brother ...
These are the things I see in that video (lessons tools teach from first hand use). I suspect others may only see "You'll shoot your eye out" and a progression that you'll evolve into using the tool as a weapon ... And as folks do not have these learning lessons they may choose diminish the value of the lessons for others (because they have not had first hand experiences).
Both of my children got a Daisy BB gun early on and carry pocket-knives daily. Both qualified hunter safety with 98 & 100 respectively at 100-yards with 22-rimfire, passed with high scores on trap range and archery also (requirements in out state for hunting license).
The first hand lessons these tools have taught, instilled at young age, include minimally an interest in physics and how things work that no book or instructor could without first hand experience learning from the tool in hand.
I suppose I need to bring this back to the OP Knives on School Grounds - Disinformation/Misrepresentation and becoming misinformed by outside influences.
When someone presents you with you can't do something because of ... some law, etc. or you can do something because of ..., don't blindly accept that "knowledge" as truth or fact. Do your own research as it applies to you, and where you are or will be. The knowledge learned can not be understood until you do the research for yourself.