From the Gun Writer comes a story about an Arizona department adding cameras to their guns. They will start recording when drawn and stop recording when holstered.
Personally, I like the idea. I think body and gun cameras when used appropriately can help protect LEOs from false accusations, bring bad LEOs to account, provide neutral evidence, and be used for training.
The trick is to make sure that the cameras are used, and used appropriately, and the chain of custody is followed.