Why does this happen so often on the left coast?

I'll have to admit that I've not used a paper map in quite a few years, but at the same time I've never relied on a GPS unit to plot my route. I suss out my route with mapping software, then use Mapsource/Basecamp to transfer my route to my GPS. I then pull up the route on the GPS and double check the accuracy. Blindly following a route that was charted by the GPS unit is simply not wise.

I won't go back to paper maps unless absolutely necessary, I just love the detail you can get with mapping software.