It's just typical Chinese behavior. Law and order in a Chinese society can only be maintained with the stick and not the carrot. If you try and be lenient with chinks they'll just take advantage of you.
It was never a problem to begin with... it's just a sneaky way to do away with the economics and optics of hiring old farts as cleaners at hawker centres.
It was important to do that after Sinkie hawker centres received that silly UNESCO heritage award.
The issue is not about human behavior. High class diners eat the same way as those in foodcourt. i.e. leaving the mess for the cleaner.
It is about providing a service a F&B should do. In a restaurant you pay for the food including clearing and tidying the table. You also pay for the same service in a hawker center but the food operators engaged a middleman to look after the cleaning but failed to do the job well. Now the owner of Kopitiam, the biggest operator own by NTUC rope in the govt to legislate tray return to save costs and headaches. Singaporeans are fooled again.
You look at the voting pattern, every 5 years, and wonder why PAP always remain in power. That gives you a strong clue why Sinkies never want to change, even though change is good for the country.