I was doing a conference in Birmingham years ago and was having real issues with one of the top table mics, noise coming through on it even with the fader right down. In the end I had to physically unplug it and only connect it when the panelist was about o speak, as long as they were talking there wasn’t an issue so it worked, long evening for me though. In the morning leaving the venue I realised the rest of the block was the West Midlands police hq and the combination of the XLR cable and multicore were working as an aerial picking up their comms traffic.
When I was at the MOD there were occasions when the instrumentation teams had picked up radio signals when using really long cable runs