What if your guest kept his gun in his car? Are you going to go check it to see if there is a gun in it?
If you are anti-gun, yes you will.
Tell me if I have the right to do so. If yes, then there's nothing more to be said. It's my right. If not, then show me the legal or moral basis for you argument. Tell me why I couldn't do so. What are the rational bases for either argument?
Make the case.