Well, he's never drank wine while pondering his bike I'd guess. Some wine does amazing things for your pondering abilities.....

I mounted up a 23 front and 25 rear on my new Redline SS. But I did it knowingly since these were the two tires that were fronts up to recently and were not all worn and cut up from being rears. See my post in Commuting on the ratio of front to rear flats to know how I ended up with two odd sized "fronts" on this bike. The old rear tires looked like jungle animals had been gnawing on them from the number of cuts and tears.....

Oh, and the bike is riding just fine with this combo. It's only a silly 2 mm's after all.