Originally Posted by Siempre Viajando

Yes, you do have to worry about that. Your statement presumes that the driver has no interest in doing anything other than getting you to your destination and receiving the negotiated fare. But if he has other motives, like to rob you, one clue is that he deviates from the most efficient route, presumably to take you to where his buddies are waiting. There he miraculously runs out of gas (and his gas gauge isn't working, so who knows?) and then you're exposed and at risk.

This routine is not all that common in Lima but it happens, believe me, so you do need to pay attention to the route the driver follows. And of course if you don't know the city and don't know the most efficient route, or you don't have any sense of direction, well, then your risk increases. That's why this was on my list of risk factors.