I'd have snorted with laughter, but then covered by saying it was a snort of derision. But secretly I'd laugh about it all day, and when there were now grown-ups around, I'd tell my district so they could have a laugh too.
I just realized a great strategy that could be used here. By publicly exposing the church on the web and then by a lot of us here asking the missionaries these questions online, here is what happens. 1.) The missionaries become gun-shy any time they suspect anti-mormonism (real or imagined). 2.) Non-members start asking the hard questions. 3.) The missionaries can't distinguish between people from ex-mormon.org and true perspective members when in chat. Result: (perspective member) I heard that Joseph Smith married a fourteen year old girl. Is this true? (missionaries) chat session ended. This can't be good for the church. So to those who are engaging the missionaries this way, good job. It's working.
I remember reading something on this board some time ago about a husband who told his wife that church members were denying a certain doctrine nowadays and she didn't believe him. The wife was a member, the husband had resigned. So, to settle it, the husband suggested they go on the missionary chat. The husband asked his question and, true to form, the missionaries denied it, much to the wife's surprise. He then told the missionaries thanks for helping his wife see how church members lie. And for the life of me I can't remember what the doctrine was, there are so many to choose from that they lie about. But it was pretty sweet to see missionaries HELPING to steer a member out of the church.
So, yes, I think the missionaries have no way to know who is a curious outsider and who is a baiter. If it's an outsider, they get to see how cagey and dismissive they are. If it's a baiter, we get these very entertaining transcripts.
I called the missionary chat 800 number a few months ago and was connected to the Los Angeles temple's visitor center. Two young female sisters serving there replied to my questions.
I have had the missionaries at my house many times trying to get them out of the cult. I'm not sure it worked BUT I don't hear from any mormons now. NONE.