I don't know if this counts since I wasn't on a bike at the time, but about a year or two ago while strolling along the river walk in New Orleans, not too far from where the Natchez docks, I saw a couple engaged in flagrante delicto sex on a park bench. This was about 4:00 in the afternoon, on a sunny weekday. No attempt to disguise what was going happening and no apparent notice of people walking by.