I think we all do a bit of TDD, just not the extreme kind. If you already have the code and now you're trying to extend it, thinking about how this is going to be done and writing a few tests around the usage makes sense. It also makes sense if you don't have the code but you do have a way to structure the code in your mind and you can figure out what parts you can build and test first.
So while it's not TDD in the pure sense (it's more like Test Assisted Development) it is leveraging the spirit of TDD.