First, simpler countermeasures are better countermeasures many times.
RE the UAV, shielding from any downward signals reduces the interference. As for "really big" jamming or spoofing, you seem to not know of the inverse square law. One does NOT require a massive transmitter to overcome an Earth bound receiver. The signal is incredibly low arriving to a receiver, when transmitted by satellite.
BUT, you hit the nail on the head for backup recovery systems, though I'd not go so much for visual, but perhaps an old fashioned intertial guidance system, where recovery trusts the intertial system over the newer software based system.
As for Adobe, less and less Adobe products are being installed by enterprise systems, unless they're mission essential. I'm personally considering removing their tangle code from my systems too. Adobe seems to not have learned that security is ESSENTIAL in software development. Even Microsoft started to learn THAT lesson!
In the long run, it's cheaper to have secure code written than to have weekly Adobe patches being written!
Hopefully, Oracle manages to secure THEIR java code even better.

The UK Military regularly carry out "GPS Jamming excercises" in some locations, and these are notified to the public by OFCOM.
http://www.ofcom.org.uk/static/subscribe/select_list.htm
Example notification "NOTIFICATION OF GPS JAMMING EXERCISES
RAF SPADEADAM, CUMBRIA, MARCH 2012
Dates: Between the 5th of March to the 9th of March 2012 inclusive.
Times: 0800 -1800 GMT.
Location of MULTIPLE jammers: based within 5km of N55° 04.000’ W002° 34.000’.
Frequency: A 24 MHz band centred around 1575.42MHz (GPS L1).
Total Power: Up to 10 Watts EIRP.

It is stressed that, as in previous exercises, Safety of Life operations will at all times take precedence over exercise activities.

Ofcom stakeholders should contact InfoGPS.Notices@ofcom.org.uk"
I've never been near enough to one of locations, at the right time to see what effect it has on GPS SatNav units.