So in PLA it says that Pokemon can shrink themselves and that's what happens with a pokeball - they shrink themselves intentionally to fit inside, it's not some tech of the ball shrinking them. Effectively it seems like it's about the Pokemon consenting to go inside, right?

(a) It wasn't always like that, was it? (b) if they're deciding to shrink themselves and go inside, why does the game still work along the lines that beating them up, setting them on fire, putting them to sleep, poisoning them etc all make them more likely to choose to shrink?