Why T1 relaxation does not give off RF signal?

[T2_JudgementDay]

Hello, first of all great site.

My question is although T2 relaxation (dephasing of Mxy) can be pick up by the RF coil why can't T1 give off a signal as well? I understand that a magnet moving (across a coil - Faraday's law) gives an RF signal. That's essentially what Mxy is doing. But why does Mz not give off a signal?