I decided to laugh. It's a reasonable hack, but not a particularly dramatic one for me. After all, he's just created a very long fixed-extension tube with no transmission of electrical contacts. Now if he'd managed to make a bellows that had adjustable length I would be seriously impressed!
An interesting hack, but not the ground-breaking project that some people on the 'net have tried to make it out as...
BTW, where he decided to use black paper inside to cut down on reflections, I would simply spray on blackboard paint: has worked well for me in similar projects in the past. Using a body cap as the basis of a lens mount is also the basis of the pin-hole "lens" project I discussed a while back.
It's interesting to note that his definition of a Pringles tube is quite different from the cardboard constructions we get sold in Aus...