Do I have to show my receipt when leaving the store (AKA shopkeepers privilege)

The short answer no you do not have to show your receipt. Long answer, well it’s a lot more complicated. Shopkeepers privilege does allow for you to be detained for a reasonable amount of time if there is probable cause or a reasonable suspicion that you have committed a crime on the premises , or that you have stolen or are attempting to steal an item. It just depends on how much time you have to waste by being wrong.