A hawker centre or food court is a commercial establishment, but there is nothing to stop you from clearing your tray like in a fast food restaurant.
Once I had a colleague who visited from a European country, after eating in a fast food restaurant, he promptly cleared his tray, while I was prepared to leave mine. If you consider the consideration perspective, clearing not only helps the cleaners, it also allows other customers to be able to take your seat faster. If you expect your tray to be cleared for you, perhaps you would expect it to be served to you as well. I hope you are not one of those who peers intently at his mobile device at a crowded foodcourt or a fastfood outlet during lunchtime either.
Don't always let going against the government influence you against ALL government policies or initiatives. Not every single one of their policies or initiatives is going to be bad, although the high handed and arrogant way they try to push them on impressionable sinkies can certainly be disgusting at times.
The problem is not ALL their initiatives and policies. The problem as I have said time and again started more than 50 years ago, with someone whose death will actually make no difference because his mentality and mindset has already been acquired or inherited by many. :(