I don't know if the other responders have ever set foot in Singapore, but you're right that it's quite westernized in the sense that a Westerner's first trip to Singapore won't be overwhelming (certainly not negatively) the way it would be in many other places.
They have their laws, and you're better off not breaking them, but none require you to be consciously aware of what you're doing every second of the day.
As for the bumble gum thing, it's commercial import and sale that's prohibited. A tourist chewing gum won't get into any trouble. Is it a silly law? Maybe, but Singapore has a lot of people yet is very clean...and besides, it's not like western countries don't have silly bans.
They have their laws, and you're better off not breaking them, but none require you to be consciously aware of what you're doing every second of the day.
As for the bumble gum thing, it's commercial import and sale that's prohibited. A tourist chewing gum won't get into any trouble. Is it a silly law? Maybe, but Singapore has a lot of people yet is very clean...and besides, it's not like western countries don't have silly bans.