I grew up a JW but my parents were not regularly attending services at a KH. They used to, and were thoroughly indoctrinated though. As is the JWs habit of visiting non-attenders, 2 sisters came to my mom and dad's door one day to inquire of our well-being. My mom told them that she had been witnessing to a co-worker who was from Elmbrook Church (back when Stuart Briscoe was lead pastor and on TV). After pleasantries were said, the sisters left.
The following week, 3 elders from our local KH came to the door. After greetings, the lead elder stated that these 2 sisters had reported that my mom had visited Elmbrook Church! How the story got so twisted, I do not know. But this lead elder started sputtering that visiting another "worldly" church was grounds for disfellowshipping, and that my mom should not do it again.
My mom explained that she did not visit another church, but that the fella she was witnessing to was from Elmbrook Church. After cross-examining her about how she even knew of such a church, she said that she did because they were on TV every Sunday morning. It was obvious the elders did not believe her, and my dad finally came to the door and told them to leave.
So, I am assuming that they were "marked" somehow, as no one from the KH ever came back again. The only contact they had with the JWs after that was that an elder would try to visit my dad in the hospital to remind him about the rule against blood transfusions, not to find out how he was doing! Sigh.
How about you guys? What has been your experience in situations like this?