That won't work as the same bad actors typically dabble in CC fraud as well. They will typically already have thousands of CC numbers at their disposal.
India, Midde East, Turkey, Russia, China, South East Asia (except Singapore), All of Eastern Europe, Africa and island nations.
It immediately reduced the amount of fraud and spam. Sure you might miss out on the <1% of your revenues but its a tradeoff I'm okay with.
or is this another one of your alt nick you periodically sign in from?
Having worked in the South African tech scene and for a UK company, every spam/dos detection I've seen has been from everywhere you mention except Africa and island nations.
here's the trade-off. Make you decision.