I've got a Checkpoint that I'd love to put an overlay on, but I'm not sure I have the skills to strip the entire PF to install it properly. That got me thinking about if putting an overlay on top of a playfield protector would work. So, I searched around and found that Pinball Center actually makes some printed playfield overlay protectors, but unfortunately not for the machine I want it for. They do however have just the overlay.
Why is this a horrible idea?