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It does something that's completely useless since you're already being tracked by other means. By the mechanisms of physics, you can't have untrackable wireless communications. It's not how radiation works.
If what you're suggesting is that airplane mode prevents you from being tracked, it's not necessarily true; airplane mode leaves certain radios online: http://wonderfulengineering.com/google-tracking-movements-ev...
You can carry a phone inside a Faraday cage, or a phone without those radios. I think this remains consistent with my comment.
That does absolutely nothing. If you don't want to be tracked, don't carry a phone. It's the only way.