A club I use to belong to went through this whole discussion and it was "shown" to us that it is required. I personally don't care one way or the other but we had a couple of memebers whop thought it was a big deal and did locate the "requirement". Whether it was AMA or FCC I do not remember. I am not going to spend time looking for it, or arguing over it so if it is it is if it isn't it isn't.

If it isn't them why is it included with every transmitter sold in the US?