Just to clarify on the ban.

The ban is on the sale and import of chewing gum, not on the consumption of chewing gum itself. The maximum penalty is a jail term, not a death penalty nor caning.

Though the link below doesn't mention about the sale, I do remember that the sale itself is prohibited.

(http://statutes.agc.gov.sg/aol/search/display/view.w3p;page=...)