Hi Steve!
I'm afraid it wouldn't help much in the day to day, like loading the bikes onto buses and such, but for packing and longer transits I've always had good luck demounting the mudguards/fenders from their mounting points and taping the blade (center section) to the wheel/tire.
This seems to prevent snags, fractures, and knocks very nicely because the 'guard hugs the contour of the tire and is fully supported from beneath. Thorn's attachment system would make this much simpler than it has been on my other bikes.
Hoping this will help.
As a last resort, any number of Japanese cycle-tourists must transport their bikes in RINKO bags with the wheels off in order to take them on trains and subways. Many of these bikes have large diameter 700C-wheels, so the problem can be severe.
Their solution has been to chop the fenders, then sleeve them one over the other with enough overlap to allow a through-bolt or two through a bridge section. They also have bridge sleeves the blades can slip in and out of, to be stored detached and hugging the tire as described above.
Perhaps something similar would make a workable solution for you if you only have need to detach the protruding ends. Cutting the SKS Chromoplastics carefully and overlapping them for 4cm or so and using inner and outer washers with a pair of M5 stainless or (preferably to reduce weight that could lead to oscillations and fatigue fractures) nylon bolts and nuts.
Photos of the stainless steel or aluminum alloy RINKO fenders are here:
http://velo-orange.blogspot.cz/2010/05/rinko-fenders.html?m=1 A photo of a fully compacted 700C-wheeled RINKO bike is here:
http://janheine.wordpress.com/2014/05/22/summer-2014-bicycle-quarterly/ This one also has the sleeved fenders an can be fully compacted to this state in only 12 minutes.
Best,
Dan.
