Satellites have very constrained transceivers. This is not only for regulatory reasons but efficiency. It's a literal waste of power to leak noise into non-targ

Satellites have very constrained transceivers. This is not only for regulatory reasons but efficiency. It's a literal waste of power to leak noise into non-target bands. Everything from the transceiver electronics to antennas are tuned for target bands. Satellites broadcasting stray signals is rare enough to not be a thing. Interference with GPS and other signals overwhelmingly comes from ground based sources.