Adventures in tramland

Hong Kong is a bit like 1930s London - in that it's got trams, and double decker buses (and can we say something about casual racism, or were there domestic helpers to not give days off to back then too?)
It's also a bit like London in the twenty-first century (am I damning it with faint praise here?) in that it has contactless cards for using public transport - Oyster in London, Octopus in Hong Kong. Being disorganised, I had a negative balance on my card this morning, so when I came to disembark the tram outside the HSBC building, the reader made a noise and the driver told me to put money in.
Now, if you're ever in a foreign country, the standard response to *anything* is to act dumb and carry on, and I didn't have change to hand, so off I set, assuming nothing else would happen. Instead, the tram driver sets off after me inside the tram. There I am in a crowd, with the tram alongside me at walking pace, with the driver yelling "put money in!" So I fumbled for a while, and stuck in a $10 piece, which placated him.
Several questions arise:
Firstly, it was a $2 journey, and I didn't get change. Should I now try to defraud the MTR corporation of $8 to get the balance back to where it should be, or is that a fine for not paying up in the first place?
Secondly, it's a tram. It runs quite literally on rails. I'm not sure that the best revenue protection policy is for the tram to pootle along parallel to anyone who doesn't pay. How long would we have got if I'd carried on walking? Would the tram driver have stopped when we got to a crowded crossing, or ploughed through them in pursuit of my $2? And if I had got away, would my picture have been pasted up across Hong Kong's public transport stations, warning people of the dastardly fraudster? I almost wish I was like the drunk bloke I saw once, sneaking out the back of the tram without paying $2. He was a winner in all of this.