Not had quite as an impressive guitar rig as that, but it reminded me:
A few weeks ago I was fixing an audio console at a French broadcasting house, and at 1am-- shortly after starting my testing, their QC chap runs in and tells gets me to stop... they hadn't unpatched the console from the transmitter, so all my testing had been going out on French TV! Was amusing, but it's just a shame I hadn't got round to checking the Talkback to PGM function :) Thought your story was going to pan out similarly!