Since this IS the CR list, I'll try this from the historical perspective -
I would argue that riding brakeless fixed-gear track bikes on city streets as practiced today by couriers (and those influenced by them) in the U.S. is an example of the dead hand of history. In America, if you rode fixed after, say, 1920, it meant you either raced, or you had learned from those who raced. Riding track bikes was something based in urban enclaves that had ties to either extinct or still existing tracks. The culture was passed on by guys like Gene Portuesi and others, who had ties to racing.
Riding brakeless was less of an issue then, as there were fewer automobiles on the roads - AND the folks who rode fixed probably had learned directly from someone about things like using the track mitt, etc., to control speed. I suspect Ted Ernest could comment on how he learned to ride, and from whom.
So far I've found exactly ONE cycling manual written and published in the U.S. from the interwar era - Roland Geist's 1940 Bicycling as a Hobby. I'm working from memory here, but Geist writes about fixed gears, and somewhere in there is reference to riding fixed on the road - with a front brake. I don't know if Geist was influenced by British thinking - it was sometime in the 30s that British traffic law was changed to require a brake of some sort on each wheel, with a fixed gear with lockring recognized as a brake - but I suspect he was, as he also wrote about touring, and 3- and 4-speed touring machines. I don't recall if he wrote about what size gear to recommend for fixed-gear riding.
We've discussed British practice, right? As a general rule, front brake only for the racing set and time trials, two brakes for club bikes and touring, right? I want to say it was Reg Shaw, but it could have been Camm, or both of them, even, who advocated 65-in gears for men and 60-in gears for women.
Italian practice, as described in the C.O.N.I. Cycling manual, called for lower gears still - 44x20 or so, maybe? - in the 1000 kms of fixed-gear road training the book recommended. There, though, riding fixed on the road is a means to an end, namely better form, spin, and supplesse, rather than just riding fixed-gears for the sake of riding fixed gears.
I don't know if there really was a French tradition of fixed-gear on the road after the earliest years - there's one photo of an older gentleman riding a fixed with a lone Mafac up front in the Durry/Wadley Guinness cycling book, but that's mighty slim evidence, and he might not be French, so there.
Somebody out there is bound to be able to do a better job with the above than I have. Have at, and feel free to correct me - all I ask is that you be gentle ...
Russ Fitzgerald
Greenwood, SC