Lima is a dangerous city with high and sometimes violent crime. You have to keep close track of your belongings, and you find you think twice about trusting people. Even your cab driver. Cabs in Lima are mostly unregulated, so anyone can be your driver. At night when I would taxi back to my hotel I’d ask to be dropped at a busy intersection a few blocks away. That way I could walk home on a well lit street without worrying that the driver was scoping out where I stayed. Paranoid? Yes, a bit. But I believe you can never be too careful.