iMac security problem? There's no iMac microphone indicator

One of the things I learned when using the pure Java speech recognition software yesterday is that my iMac has no visible indicator of when the microphone is on. With the Sphinx-4 "Zip City" application you have to press a button to speak, and when you do, there's no indicator on the iMac that the microphone is on. So basically any application can turn on the Mac microphone without you knowing about it. Is this a Mac security problem? I personally don't have the need or desire to steal anyone's personal information, but that strikes me as a little freaky.