I was (politely) threatened with arrest on a British commuter train when the ticket inspector's credit card device insisted on a PIN for an American credit card.

He literally didn't believe me when I said American cards still ask for signatures. By luck there was an American also riding in the cabin who piped up to verify my story and I was allowed to pay when I reached my destination.

In Australia the same card works with contactless payment, which never asks for a signature, up to AU$100. But as soon as I go over that limit it's a card dip + signature.

Also interesting how there are such specific requirements at grocery stories. None of my US-based cards could be used in several grocery stores in the Netherlands. When the cashier looked at my cards, they immediately knew it was because I didn't support whatever networks they expect.