It won't be a fabulous day, but folks will still be able to find their way home, if they are not hopelessly dependent upon electronics and are schooled in the fundamentals.

I have been using GPS since 1991 and it was truly a great leap forward, but I am glad I was grounded in traditional techniques. I began using a USGS quad map produced in the late 1930's by a team using pack mules, plane table, and alidade - real John Wesley Powell stuff. They showed the trail network very accurately, but the topography was a bit sketchy. I nominate aerial photography as the most important advance in mapping and navigation in the last century.

A GPS will show your location, and it may show your destination, but it won't necessarily show the obstacles and traps that lie between. For that, you need an accurate,detailed map, either paper or electronic.