The PABX problem was enormous. I worked in telecommunications for 25+ years and long horizontal cable runs had to be avoided in order to prevent them becoming an aerial. Local taxi companies were the usual problem, as their signal was so much closer and stronger than general radio signals.
Over time, the insulation can wear down which can make cables more susceptible as receivers. Or a new item can be installed in the building/aircraft which creates a perfect attenna where none existed before.
You will all know of times (probably not on aircraft) when the human body acts as an aerial. Using an AM or FM radio on the fringe of reception spread, you get a better signal if you hold the aerial with your hand.