This is not a golf club or tennis club and we cant control billions of people . So when we see people who behave contrary to Islamic values , we cant say we remove your membership from Islam . They will continue to live their life in the way they like . You cant distinguish two person by looking their face if which one is muslim . I dont know if there is such a place distributes the documents people that they are Muslims , I dont have any document that proving that I'm muslim , this is not blood group that doctor can identify your religion by looking into few drops of blood .