Thanks for the very detailed explanation, I think I understand a little better the generation mechanism, if the window of available PIDs is so small, it is very unlikely that there is a shiny one, but it could be, of course. You say only 255, but if I create one that looks legit, I understand that just by looking at the PID you could check that it doesn't match the supposed limited seed.
Anyway the anti-shiny seems to me a very rudimentary procedure but that way it could be effective.
I would like to know a bit more about the back-end of event distribution and triggering, it has always seemed to me a mysterious and attractive topic.