Moron's, you can't realy on GPS's for situations like that. Its like on a boat, you need a paper chart backup.
I love my Garmin, its fantastic on the road, and even lead me on its own around DC on my way to FL!
On the way back up since we went around NYC to get down their, it lead us the same way around. Its pretty smart sometimes, I'm amazed at how quickly it will "catch on" to the route I want to take. Other times its a paper weight.
