Oh yeah... We have systems installed on a ridge with broadcast towers almost in the backyards.

We've had FM & TV stations play directly into speakers with *nothing* connected to the other end... no amp, no nothing... just wire.

Also have Preamps/Receivers in these systems that will play FM and/or TV audio on various inputs, with nothing but AC and speakers connected.

Powered Subwoofers seem particularly susceptible, with line *or* speakers level inputs.

Combinations of artful wire arranging to minimize the "antenna" effect, trial & error equipment & cable grounding, ferrite filters, and shielded cables work fairly well. Have not seen a definitive correlation between higher quality ($) equipment and rejection/immunity.