I'm sure the tennis racket suggestion is facetious, but this thread has dredged up some bad memories that I'd now like to burden you all with. For some reason, my old house (built in 1838) is a bat magnet. In recent years, we've had a dozen or so inside the house. On the first occasion, we discovered it in the morning in my 6 year-old daughter's room. We feared it had been there all night. What to do? We weighed the risks (extremely low) against the consequences (our daughter's death). Out came the tennis racket! It was ugly, and a mistake because in order to test a bat for rabies the brain must be intact. A good backhand stroke will pulverize a bat brain but good. Luckily, my tennis game is poor (for awhile the bat was actually winning), and, after freezing, just enough tissue remained to confirm a negative test result.
I am a pacifist at heart, so I was determined never to repeat that sorry episode. The next time I heard my wife scream in a pitch so distinctively high it could mean only one thing - "little brown bat on premises" - I already knew what I was going to do: Nothing. I opened the windows, and suggested we "go to the movies." She had an alternative idea, "Let's move!" But doing nothing worked; on our return the bat was gone. Total cost - $20 for movie tickets. Then, my wife insisted we call in professionals to bat-proof the house. Cost - $600!! The company's guarantee expired and, predictably, a few days later my wife let out a high-pitched scream.
Over the years, I've found the "just leave them alone" approach doesn't always work. The little buggers are small and you can't always tell when they have vacated the premises. The ones who don't make it out the first night invariably die from dehydration. (My wife's discovery of these is communicated by a less frantic, but characteristically tell-all shriek.) So now I have adopted a no-ifs-ands-or-buts "fishing net capture and release" policy. It's cheap, safe, and effective. Fun even. But I still can't get my wife to play.