I do recall a long time ago, a ground marshaller was inattentive while I was approaching the spot he was supposed to be marshalling me into. I sensed this was a potential hazard for him. So I stopped, and selected reverse on that engine, and blew him out of my way. It was icy, so he moved easily. Otherwise, I have found that apron control [of people] is the best way to assure safety. If you, as the pilot, are uncertain that people are safely away, you should shut down until the path is clear. Having a horn would suggest that it's okay to have unattended people on the apron with running airplanes - it's not.