Add Button to Check for Shader Alpha Usage in Light Path Settings

Please correct me if I'm wrong, but AFAIK, the main consideration for whether or not to enable Transparent Light Path Bounces during Cycles renders is whether any materials make use of Transparency/Alpha.

As such, perhaps we could have a button in the UI to check for exactly that -- right above or under the Transparent field (which is already visually separate):

If Alpha usage by any active shader is detected, Blender could display some kind of message with advice on setting Transparent to 0 or... something greater 🙂