My problem with the backup theory, is that, if it's left in there, if people don't regularly inspect their bikes, how will they know the steerer broke and they're just riding with a dowel holding it together (assuming it fit tight enough to maintain steering). Then, eventually your dowel breaks catastrophically, and you're back where you started with a nasty accident.
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Bikes: 1996 Eddy Merckx Titanium EX, 1989/90 Colnago Super(issimo?) Piu(?), 1990 Concorde Aquila(hit by car while riding), others in build queue "when I get the time"