When I was visiting Oxford 23 years ago (oh, now I feel old!) most of the bikes had reflectors on sticks attached to their seatposts like the yardstick you described. They stuck out to the side so cars had to give them room or they'd get scraped by the reflector-on-a-reflective-stick. (it was like a big reflective paddle)
Someone needs to re-invent them, cuz I'd buy one!
Glad BeemerBabe didn't knock you over. (and I hope you catch her some time!)