No-one on this thread has counted erections.
Some of us have said that we have seen riders on naked bike rides with erections.
Some other people on this thread think that this is impossible or exaggeration or pearl-clutching or man-hating or something. It's not.
As I have said, I am very used to naturist beaches and clubs. My parents were naturists, although it's not something I've done with my own, now adult, children. I've seen hundreds of naked bodies as a child and a teenager. Never saw anything inappropriate.
I have no hang ups about the human body. I have no objection to public nudity on beaches, in communal changing rooms etc. I don't equate being nude with being an exhibitionist or a pervert.
I didn't know the naked bike ride was happening when we came across it. We were in London with family, walking down the Mall, about to take a photo in front of Buckingham Palace and were ushered to one side by the first cyclists. All very good natured and celebratory.
So I was very surprised to see several men with erections. I didn't need good eyesight or to search them out. They were... very evident.