The Curious Randonneur posted a fender rant recently which is a sentiment I fully share. I also would add flashing rear lights to the list of rando rants. I’ll give civilians a break because they may not have ever had to follow someone on their bike for a few hours who has a flashing ultra bright rear LED light. But, I would expect everyone on a brevet to know that a flashing rear light is hard on the eyes of everyone behind them and that in many cases the folks to the rear have no choice, but to follow them for a good while. Unless you are well and truly on your own please run your rear lights on steady.
One time you know you won’t be alone is at the start of a brevet where the group may spin along for 10-20kms before they split up and there will be many people behind you to enjoy your flashing light show.
I position my rear light below the seat so that I can toggle from steady to flash to off without missing a pedal stroke. That way if it gets dark and cloudy during the day I can turn on my light and then turn it off when I don’t need it.
BTW – flashing ultra bright LED front lights are equally irritating when looking into your rearview mirror at someone who is following you for mile upon mile.