I just about never "loan" the bike out. Although wrenches and knowledgable friends have test-ridden when diagnosing problems. Not the same thing as a recreational ride.
However, growing up our local "Honda 50/65/90, Bridgestone, Vespa, Sears Compact" crowd did regularly "swap out" bikes on our jaunts around the neighborhood. It was a cultural thing. And a status thing-- you'd never ever think of asking to ride something like a Honda 160 or 305 Twin.
Kids are strange, and were strange back then.
'73 R60/5 Toaster