There are times when it is a good idea to follow the advice don't get in cars with strangers that your parents taught you when you were small. For example if you are six and a creepy man with a combover offers to show you his puppies, they are in his van, just follow him. Don't go with him!
But then there are times when it is a good idea to throw caution to the wind and climb into the car with someone you have just met and will probably never see again. Like when you get lost in Tuscany and a nice Italian woman offers to drive you to your hostel. Or you miss your bus in Ireland and rather than lugging your suitcase the three kilometers into town, you decide that it's better to thumb for a ride.
Or for example, this Sunday while I was pottering around town when an older man called out "Jennifer!" I didn't recognize him at all, but I have met so many people this past week that he probably did know me. Let's call him Mr. Hinui (because I think that's what he said, I'm still struggling with names here.) He invited me to get into his car, but didn't have enough English to really explain why or where we were going. He took me to a prehistory museum outside of town and then found me someone who spoke English well enough to explain what I was looking at. Then it was back in the car, with a quick stop at the local Circle K for some ice cream, and then we drove up to Mount Zao to see the view of all of Tahara, the Pacific Ocean, and the bay, (I'm on a peninsula.) We ended our outing back at Tahara Castle where he originally found me at the town museum, where he left me with another man who spoke English and could explain.
Mr. Hinoi, or whatever his name was, slipped out while I was watching a video at the museum so I barely had time to say arigatogozaimase for the impromptu tour.