Girls who actually use the white list on a regular basis fall into two user categories.  Some will whitelist anyone from a session that went well.  Others will whitelist repeat and better known customers.  It's great to be on the whitelist - but it's not the end all be all and doesn't get you the mileage that some folks might think.  Also, just because you are whitelisted doesn't mean that the provider won't want time to contact the one who put you on their list to find out more about you.