Google Maps isn't being used to investigate someone's death or as evidence in court to potentially convict someone of death by dangerous driving. Of course the police are going to be thorough, if other countries are clearing collision scenes so quickly it suggests to me that they aren't investigating them properly.
Sounds like you've watched a bit too much CSI to be honest, are you expecting them to just scan the entire scene with some sort of device and be able to conduct a thorough and proper investigation using just that?
