That might stop a sawsall, but would it stop a cordless angle grinder?
Haha.. Not much of anything will stop an angle grinder with a cut-off wheel. When the guy was tellin me about how they used a sawzall, I was thinkin of how I woulda used a cut off wheel. A 5" cutoff wheel will cut through the door as fast as you can move it. In many situations you wouldnt even need a cordless, if you can get your vehicle close to the door they make power inverters large enough to run an angle grinder for not much money.
I honestly can't picture how the pipe concept would really work. The pipe cant be connected to the door material, because if it was it wouldn't roll up. You can attach it to the frame, but it doesnt protect the door at all. If I was ripping through the door with a sazall, if I hit a pipe even if it wasn't reinforced I would jut angle the blade until I got the cut skip the pipe. Once the cut is large enough pull away the skin(the door) and you are in and can lift the pipe out of the way and open the door.
I can think of several ways to combat the problem, but they would signicantly reduce the functionality of the door in the first place, or take a significant amount of time to set up each time for an occurance that probably would never happen.
In the end, I found it much easier to just move away from the problem. Heading out of town, there are many many high value targets that a theif would be more likely to hit, and if you were eager enough to travel to my place, its one of those places I wouldnt bother with. I cant remember how he said it, but on one of Foxworthy's routine he was talking about theives and different looking houses. He said something about the one with the nice clean lawn and decorations would get broken into, not the one with old cars out front, tall grass, etc because that house just says "A gun lives here", LOL...