Originally Posted by GUWonder
Bahrain used to do something similar (and may still). This "faith-based" inquiry was initially aimed at Shia muslims who the Sunni ruling classes there considered to be a revolutionary "risk".
An old school friend of mine (Shia muslim) was initially denied a Bahrain residence permit on these grounds, until his employer (Citibank) raised hell and got things fixed. This was as recently as 3-4 years ago.