Two puzzles about the Bat-signal:
a) What happens if Commissioner Gordon needs to contact Batman in the daytime? Or on a night that doesnt have low-lying clouds? I can see why the tv version installed a Batphone.
b) If I were a Gotham City villain, Id hole up with a rocket launcher in a building near the one with the Bat-signal. Then when the signal comes on I know Batman will soon be on the neighbouring roof. I watch, I aim, boom.