It's not just a problem with bikes. I've been to a number of on-street car shows, where car clubs come out and their custom and/or antique cars are parked all up and down a street in the downtown area, and people stroll along and look.
I'm sometimes just amazed at the chutzpah of some people...they try to open the doors and get in, they put their hands all over the body, like checking the mirrors to see how they move, etc. Almost always, the owners are right there to stop these jerks, but they shouldn't have to.
People can be so rude.