You would think that the name of the car “Impala” would give them a clue.
But they are also most likely well aware that it’s not really a donkey, they just like the term as a nickname for the car.
I think the car manufacturers like the ally wheels because it gives them unlimited styling options. On the lot, they look better than plain black steel wheels with cheezy plastic wheel covers…They also are very easy to recycle…Special purpose facilities buy them by the car-load from salvage yards and shred them into little nuggets which can be melted down in small smelters and used to make all kinds of things…As a side-bar, the civilian Crown Vics, Marques, Towns all came with classy alloy wheels…But the cop-cars all have heavy steel wheels…What does that tell you?
Here’s a puzzler for you. He made a copper shoe and said that it was still widely used in Britain yet. Why would you ever want to put such a soft metal shoe on a horse???
I’m impressed at the answers that you all gave to this puzzler. No answer was dumb and everyt one had a valid point.
In Britain, they have coal mines that have been in use…way before man came up with any machine to haul the coal carts from deep within the mine…to the surface. So many mine passages are too narrow or low ceiling for anything but small horses and donkeys
So they still rely on small horses and donkeys to pull these carts thru the mines.
With a copper shoe, if they kick a rock, they will not create a spark that could ignite gasses in the mine.
Thanks for playing along everybody with this off topic post.
yosemite
B.L.E., I was just pointing out that the person who said mild steel was pure steel was wrong, its just carbon content and temper that that make it mild.
semantics shmemantics…
The name "Donk" came from the Impala emblems on the car, it is short for donkey. Yeah, really, donkey! Hence the nickname "Donks"
Thanks for the explanation…I learned something! The only time I’d ever heard the term “donk” used before, it was a derogatory reference to a bad poker player. A donk, a donkey, a dumb beast/braying ass, etc. Thus, I kinda assumed “donk” was a derogatory term from outside the community, not the other way around.
Bringing it back to this topic, would aluminum (which is also non-sparking) horseshoes work? Then blacksmiths could sell “mag” horseshoes. 
Yes aluminum horseshoes would work, no spark. The “mag” in mag wheels refers to very early lightweight cast magnesium wheels (someone mentioned this already…)
You DO NOT want to use magnesium for this. It sparks! They make fire starters with this stuff! If the spark ignites the horseshoe itself, it might burn your donkey! (NOT a euphemism, repeat, NOT a euphemism) Let’s stick with copper, 
Ampco is a trademark for a variety of aluminum bronze alloys that are non sparking and almost as hard as steel. I use an ampco nipple in my muzzleloading rifle and it outlasts the steel ones.
Copper-beryllium has some very endearing properties too-Kevin