Apparently, this no gum chewing thing is a no starter and fully punishable in accordance with the law. I balk when I find out the hefty price tag of said infraction (which I luckily avoided).

My wife revels in these I told you so moments but doesn't realize I have a hard time detecting the signal from her verbal noise (don't tell her I said this).

Later, I remember the worker was at the opposite end of our compartment. How on earth did he notice I was (unwittingly) playing the role of rebel, even though my mandibles were only subtly moving under a medical facemask?

CCTV.

Unless you've been stuck in your mom's basement, you know that in Asian countries there are cameras EVERYWHERE. Undoubtedly, this is why the majority of these countries' denizens are on their best behavior (not that it doesn't prevent a minority from having their foolish behavior recorded and often broadcast for the entire world's amusement/condemnation).

To hammer the point home, my father-in-law later relates to me a story of how he once found a non-negligible sum of money on the street and immediately brought it to the nearest police station. This is the default rule in this situation, because if you don't do this they will definitively track you down. The police will next broadcast the financial loss to the general public. In this instance, no one laid claim and my father-in-law became the lucky recipient.

It begs the question if this is even ethically right to do. Where is the line drawn before it is crossed into dystopian Orwellian proportions?

I don't doubt this will never happen in America, a place that it so diametrically solipsistic to the status quo environment of Asia. However, whether this is good or not is debatable. For example, note the amount of videos that exist online of poor behavior being recorded in public (with or without the perpetrator's knowledge) and the ensuing public outrage that seems to be the only form of pressure strong enough to elicit contrition (mandatory it may seem).