LOL! Ooops... sorry, that was me ;~D
Really, I am curious to know if it was a bad idea for safety, or just bad fashion sense ;~D
I know you know this, but I'll indulge you anyways. ANSI standards for bicycle helmets are not as high as for equestrian helmets. It's not the speed that matters but the height. You're falling from maybe 5 feet on a bike and from closer to 10 on a horse.