no but I once forgot to remove the top tube adapter tension bar for the bike rack. had to do my whole MTB ride with that thing rattling around
the one time Wifey & I decided to intentionally ride w/o helmets, because it was such a hot day, a cpl years ago, she crashed into a bollard on the rail trail & broke her wrist. luckily didn't hit her head, cuz her wrist took the fall.
after that, we vowed to always wear helmets. I make only 1 exception, a slow 2 mile beach trail, which stops where I hike another 2 miles on foot