Ummm....

If it's showing as in transit, it means it has been scanned at some point. If it wasn't scanned it would only show as manifested.

So the driver might not be scanning on delivery, but that is not your point, is it?

You have Paypal seller protection if you can prove postage. Which ANY scan event on a C&S parcel will give you. Good luck with the couriers. I assume you have factored the negatives you will receive when the buyer isn't home at delivery time and has to travel to the depot to pick up into your business model.