It's happened to me twice. Once in Burkina Faso, where the second best hotel in Ougadougou was overbooked, and not even my police escort could get me in - got re-booked into the third best hotel in Ougadougou - much better than my colleague, who didn't have the police escort, and was rebooked into a very dodgy hotel in the back end of beyond.

Second time London, arrived at my 3*, got walked, they gave me money for the taxi, but not enough, but moved to a 4*. However, when I arrived I was told that hotel was full too! Threw a tantrum (first one ever in a hotel lobby) and strangely, a room became available. And still managed to make it for the last five minutes of the meeting I had gone to town for And, had to pay for the hotel, though at the 3* rate.