This is kinda how it works in China, according to Amber Scorah in her book "Leaving the Witness". You make friends with householders in informal settings - such places as the launderette, café, library etc. You don't raise the issue of religion until much later, initially explaining your faith in terms of Christian bible stories etc.
Because JWs are banned in China it may be years before you raise specifically Watchtower doctrine.
I always thought it was somewhat cruel. To befriend someone over years and years and then just drop them if they aren't interested in becoming a JW. At least with the western Bible study model you know where you stand from the start (well...mostly.I know this point is arguable, there's still quite a bit JWs hide from Bible students)