In the second image here [1] there's a security seal on the payment closure as a whole; I'd imagine a simple security seal along the side of the card scanner intake would thwart most would-be card skimmers, no?
At that point the employees could just make it part of the standard inspection and it'd be more obvious to customers if they were missing.
At that point the employees could just make it part of the standard inspection and it'd be more obvious to customers if they were missing.
[1]: https://cdn.sparkfun.com/assets/learn_tutorials/6/9/4/Gas_Pu...