Inadvertently transmitted cabin addresses can cause mirth at times, but can also bite. Many moons ago a domestic jet inbound to Heathrow was told by Heathrow approach to "leave Bovingdon heading 140, no delay, runway 28R" as was the norm in light traffic periods. Shortly after came a cabin address over the air: "apologies for our late arrival, this was due to ATC delays". Nothing rancours an ATC than to be blamed for delays as a result of congestion, especially when there aren't any! The next transmission the errant pilot heard was "enter the hold at Bovingdon".............. It wasn't me on radar that day, but I would have enjoyed doing the same.