Once upon a time back when sealed Genesis games were only modestly above CIB copies in price, I bought a sealed Gunstar Heroes.
Having previous success with VGA I sent it in to be graded and expected a 85 grade or so.
It came back ungraded and they said it was a reseal.
Trusting VGA that it was a reseal I opened the Gunstar to confirm CIB contents. I found it was indeed brand spankin' new, fruit roll up and insert poster and everything. Pin connectors on the cart immaculate and perfect under magnification.
I was so mad that I pretty much sold my whole collection.
In retrospect I should have just been happy I had a 100% CIB minty copy, but I got all bent out of shape for some reason.
Moral of the story is that VGA is staffed by actual human beings who sometimes make errors. They are not God almighty.
Genesis games come with a variety of different seal styles, depending on the company and print run.