i had a job over christmas at uni way back in the late nineties. I was installing training systems in branches of lloyds tsb bank. I was working all over the country, previously before this job the furthest i had driven from my home (i had only been driving for a few months) was 50 miles from leafy surrey to bluewater in kent.
I worked in central london, hull, leeds, newcastle and south wales over the course of this job, and i managed to navigate my way everywhere with nothing but an AA atlas.
while it is possible to get where you need to go using good old fashioned paper maps, the minute you hit a built up area you don't know, you are in trouble. Try finding somewhere legal to pull over for five minutes in london while you check your A-Z, the cctv cameras will be all over you and you will get some lovely letters through the post delightfully telling you you have won the chance to pay westminster council the princely sum of £80.
Sat navs are a great aid, and in some cases a complete god send, but as has been said, people who are stupid enough to follow them without question are..well..stupid. I have co-pilot on my smartphone, it does what i need, it gets free updates, it gives me a backup when need reassurance on a route. its no replacement for actual knowledge, but who has the time to learn all the routes they need to take ahead of time?.