After thinking about this for a while, the shooter's eyes are (or should be) focused on the target, making it difficult to see anything moving as fast as a shot pattern in between the end of the barrel and the target., So I can understand why it would be difficult for the shooter to see the shot in-flight. Bystanders, on the other hand, are in a much better position to see the shot in-flight because they are not so focused on the target.For me, anytime I see my own shot my head is off the stock and I missed, but seeing others' is pretty easy. I think with my head on the stock it takes my eyes a bit to refocus after getting whacked with a gun. I have a new sliding comb setup as soon as I get it inletted and finished. Maybe I'll see my own shot then.
Copper plated shot like the old Federal live pigeon load is really bright under the lights. I used to use copper plated shot for my back fence loads, but it made it impossible to get someone to shoot through. If they didn't see the copper they knew I had slipped in a slow load, lol.
I tried painting a bag of shot spread out on concrete with dayglo orange. I evidently didn't let it dry enough as all the loads looked like slugs. The paint glued the shot into a single lump.