Being led astray may not always be the maps. I have had my GPS units (various brands over the years) pick routes at times that just don't make sense. The correct roads are all there, but something in the programing leads it to pick a bad route. I had one GPS that would never program a route over the Pacheco Pass, Highway 152 in California. I live east of that pass and a lot of things I want to go to, like Monterey and Santa Cruz, are on the other side and the GPS always wanted me to go all the way North to Highway 580 and then come back down. Which ever side of the mountain pass I was on it would do that. And it would keep recalculating and trying to get me to go that way until I got onto the Pacheco Pass and then it would recalculate and tell me to go straight ahead and cut 100 miles off the route.
Some friends and I ride quads up the mountains just below Yosemite. There is a forest service road we usually park out trailers at and start from there. At the start of this dirt road is a sign that reads, "You can't get to Yosemite this way, don't believe your GPS." Actually you could get to Yosemite that way, but only on a Quad or a good 4wd like a Jeep. One day we asked a guy that lived up there about that sign. He said one of the big car rental companies out of SFO had GPS's that would pick that route to get to Yosemite. So tourists from all over the world would get in their rental car and program in Yosemite and end up on this dirt road. And he said many of them would trust the GPS and keep going until they got stuck. He said he had used to his back hoe to pull out at least 10 and another neighbor had pulled out at least that many too.
Not only do you have to make sure your maps are updated, you have to make sure the thing is picking you a good route too.