A co-worker had a similar experience with a JW neighbour. Both had children about the same ages and they would end up chatting at the park while the children played. Eventually the JW started Witnessing™ to my co-worker, and even though she wasn't interested in becoming a JW herself, she remained polite and respectful to keep the "friendship" at the park going between herself and the JW and as well between the children.
I had kind of mentioned that I hoped the JW wasn't just being friendly with her in an attempt to recruit her. I told her how JWs keep track of the time that they spend discussing the Bible with non-JWs and turn in a monthly report, and that I was guessing that this is what was happening with her too. She was shocked! How could this nice JW lady who was so sincere and so genuinely interested in her and her family have an ulterior motive? I just said "You know what? I hope I'm wrong and this lady is different from the way Jehovah's Witnesses are trained to be. But I'd also feel really bad if I didn't say something to you now, because I know it hurts a lot when you find out that a Witness has only been friendly with you for the purpose of getting you to join the religion. You're my friend and I care about you enough to alert you to that possibility. I know that it happens because I used to be a Witness and that is how we were trained. I just don't want you to get trapped in a conditional friendship with this lady, based on whether you agree to get involved with her religion or not."
She dropped the subject and didn't mention a thing for a couple of months. Then finally one day out of the blue, she came to me and told me that I had been right. The JW lady had started walking home from the park with my co-worker and then continued on her way to her own home. After about a week of that, on Saturday morning the JWs came calling, and it was the JW lady from the park with her husband and children, all decked out for Field Service™ and offering the new Learning From The Great Teacher book. My co-worker told me that it took a lot of courage for her to say that she loves talking to her about the Bible, but she has no interest in joining the Witnesses or even studying with them. The JW lady informed her that she wouldn't be able to chat with her in the park anymore. Just like that. And my friend realized that this lady wasn't interested in her friendship at all, just in logging time on her Field Service Report™ at my friend's expense.