Webcam input - how to use this successfully?

During baptisms, we want our cameras to appear on the projector screen. To do this, I'm feeding the camera feed into the Mac (using a BMD WebPresenter). I ideally just want to add this as an item in the schedule, or have a quick screen to show the camera.

However, as far as I can see, the only way is for the camera to be the "bottom layer"... so I created a Quick Screen that had absolutely nothing on it, and that's worked well.

However, now, if anything is added which is not 16:9, we see the camera in the background which is really frustrating. I know you can add a background to the items, but the reality is that, as the schedule is built on a different computer(s), which don't have this camera, and by a variety of staff, it's often forgotten and not noticed.

Unless I'm missing a more obvious option, having it always in the background is "too dangerous" and so we've had to turn this feature off. I feel like having it as a background option per-item (for when you want words), and as a stand-alone item which could be added into the schedule, would be a much more useful, and safe, option?

Thanks for your feedback!

A video that was widescreen:

A slide that was 4:3: