I am a US resident. I went into this store and made a purchase and put my credit card into the slot. Without asking the clerk pushed on "merchant conversion". I asked why she did that and was told she knew I was an American citizen by my driver's license which she saw.
I let it go and came back to my computer and learned I was charged about a dollar more (about 5%) than my credit card company would have changed with the automatic conversion they provide.
I called the store and found them defensive although they did offer to refund the difference which I declined
So, beware. Your credit card will always give the current conversion rate to you the instant you make a charge. And no merchant fees read more