First of all, if you quit eating those psylocibin mushrooms, your memory would probably work enough to find stuff.
Second, I cannot see this happening to a point that we really have to worry. The US military uses GPS systems (in fact it was designed just for them) and I can't see them losing that all important system to a broadband company.
Also there are the GPS companies out there that would really lose a lot of money if this does cause problems. That would put an end to it pretty quick.
Then again, maybe it is the thing of the future and we will all one day be using broadband to find our way in the fog. Even the US military.