Or maybe they are what Douglas Adams called teasers...I don't have my Hitchhiker's Guide handy, but the basic idea is that rich kids with nothing to do go to planets that haven't made interstellar contact, land in front of some poor soul who no one is ever going to believe and strut back and forth in front of them wearing antenna and making silly beep-beep noises.
"Rather childish, really" Ford Prefect
Just another theory
Rob