I am always appalled at how little scientific, mechanical or intuitive logic resides in the middle classes of American society. The average European housewife could look at that flag and realize that a mechanism to lift it out of the way could never be operated by a thumbshifter. That same housewife (homemaker) would also realize that such a device is the antithesis of the bicycle ethic. A pedestrian walking around with bumpers on to delineate their "personal space" would quickly find themselves in a fistfight upon actually contacting another person with it as would inevitably happen. No matter how remote the setting, if it involves enough "close" situations to require a device like a side marker flag in the first place, would also see that side marker flag inadvertently contact another fixed or moving object or person. More to the point, the rider would forget to raise the flag when it needs raising most. It would happen. I have never understood the wisdom of car topping bicycles around so I would never do it, but... now that I am in a club and get to talk to lots of riders, when I hear about the many, many, many instances of driving into the garage with thousands of dollars worth of tandem strapped to the roof.... to say nothing of the thousands of dollars worth of damage done to the garage facing and door mechanisms... this is even after a previous incident and a warning sign on the garage door to check for bike on car roof... CRUNCH!... well after all that you realize how fallible human memory and situational response is... anyone who has posted in this thread about the at will retraction and deployment of such a thing as a side clearance marker is completely and fundamentally in denial about the human psyche. It ain't gonna happen. That flag will be out there waving just when you would rather it not be... FWIW.

H