Have you ever used sneaky measures/techniques to avoid someone who was annoying you?

So we have this coworker who basically traps you in a conversation, once she starts talking she can’t stop, and she’ll literally be at your desk for a half hour talking about things that are completely unrelated to you or your job. Lately me and my colleagues have been calling each other whenever she’s at the other person’s desk, and when she sees their phone ringing she gives up on the conversation and walks away. It’s been a very effective technique, albeit a little sneaky. I guess this is what we do as opposed to telling her we are too busy to talk at the moment. Have you ever (or do you now) used a similar tactic in order to avoid someone who was annoying you? Please tell your stories (about work or in your personal life).