Here's the rub: if you break the ring and remove the cap in order to be sure the foil seal is intact, you cannot return the product. So be sure you are buying something that you will definitely be using.
This is good advice but these gamers know how to make that cap look and feel sealed. They are conniving critters. If the cap is a solid color like most are then that adds to the difficulty of checking the internal seal.
Why the oil companies haven’t all gone to transparent caps or used a shrink wrap on the outside of the cap is baffling.