So far the only thing I have found puzzling regarding sirens, is that in some countries fire engines, police cars and ambulances sound differently and in some they don't. Then a taxi driver made me realise a whole other, literally alarming, function of sirens:
We were driving towards a bank and a police car, sounding its sirens, overtook us and halted outside the bank. The taxi driver then presented an interesting theory: The police would sound the sirens to allow for the robbers to get away before the police arrived. I started thinking about corruption and the Vatican and so on. His explanation, however has a beautiful simplicity: If the robbers get away, the police work gets much more interesting. He cited several examples of cases where the police had been forced (by this theory deliberately) to travel all around Europe in order to track down the wrongdoers.
This is a mechanism often bugging me in films, where in order to make the plot more exciting, someone does something stupid or at best rather clumsy. I now start to suspect that there might be a few cases of this in real life as well. Thanks to this taxi driver I shall now be able to spot these cases of planned thrills.
