This thread has helped me decide how I'm going to deal with my mom the next time she tries this stuff. I have a 9 month old daughter, and ever since she was about 4-5 months old, she's cried whenever my mom walks into the room. No one knows why, she just does. Now, when my mom does the "woe is me, why don't you love me, you'll have to come stay at my house and I'll make you love me" talk to DD, I ignore her. She knows that's not going to happen and I just don't even feel like it needs to be addressed. But one day a few months ago as she was leaving my house, she held DD, who started crying. I said jokingly, "Wow, what did you do to her?" She started in on "How could you say I'd do something to that little girl, I'd never do anything to hurt her, I love her," etc etc. The first few times I reassured her and said "I know, I know, it was a joke, she's just a baby, she just needs time," on and on.
Then she brought it up at Thanksgiving. I said "You know that was a joke, right?" She said "Yes" and then carried on with her woe is me speech. So next time she says "You said I did something to DD!" I'm just going to say "Yep" and leave it at that.