skin
I've met people who say "Oh, I know a JW" (I live in a small city, pop. about 600,000). So I ask them the JWS' name, and realize they were born in, but yeah, I knew them all my life, and they never were baptized, and haven't been to a KH in 35 years except for 'memorial services' and 'weddings'. Some of these people are my cousins.
Some of those people live in unwedded bliss, and are in no way, shape or form a 'real' JWS. When it comes to surveys and such, though, when asked their Religion, they say "Jehovah's Witness". That's what I think.
*Edit: And I think that's NORMAL. Most of my friends never go to church, but if they grew up RC,they might say they are RC. etc.