hooves, Hong Kong racing was apparently a gold mine 20 years ago. The bettors' capping skills were virtually non-existant. Betting by lucky number was an important component of most pools.
A blackjack card counter named Bill Benter moved to Hong Kong, developed his own software to look for inefficiencies in the Hong Kong pools and made multi-millions. Sophisticated groups from Australia and elsewhere followed, and things eventually got tighter (more efficient). I don't know what the situation is like there now.