So let me see if I understand, a long post is "dangerous'? Now I'm sure that this makes a lot of sense to, ... well, you.

You are right of course, the action of puting a load leaf upside down on the top of the spring stack will lower it two ways. As you say, by forcefully deforming the spring sownwards & by acting as a thin lowering block, but the action of the spring is now severely compromised, & the rebound action is now severely & forcefully limited.
In my view, this is potentially unsafe, but what would I know, I've just been a mechanic all my adult life & been playing with modified cars since I was 14.

Ever wonder why this method of lowering is not widely used in the performance car industry by those that actually know what they're doing? It doesn't take Einstein to understand it.

Just clarify this for me will you.
You are saying that poverty [or at least limited funds] is an acceptable reason to adopt unsafe practices & that safety in vehicle modification is only for those who can afford it? That's how it reads to me & I reject that concept out of hand.

If you cant afford to modify a primary safety element of the car correctly, properly, & safely, then don't do it at all untill you can afford to do it. Hell, that's what I have to do.
In a ridiculously extreme example it could be seen that your policy would accept the use of water in brake systems when brake fluid proves to be too expensive. [this is an 'illustration of a point', so don't get excited]

So lets summarise
I'm 'dangerous' because I write long posts.
Unsafe modifiactions to primary safety components in a vehicle is acceptable to you as long as you cant afford to do it properly.
Dodgy un-engineered home grown conversions on your car are just fine as long as the inspector is not clever enough to see them as being crook. [assuming that they are crook]

I know who'se 'dangerous' around here.