I grew up in a beach community, and we rode everywhere on our bikes. We often gave each other rides, and occaisionally even gave two people a ride at the same time. Sometimes we’d have battles between bikes, each with a passenger, riding alongside each other trying to knock the other off balance. We also learned how to do the opposite — ride one bike and bring another (empty) bike with us, which is harder than it appears. But we had limits: I don’t think I every managed to ride no-handed with someone on my handlebars.