This happened to me recently with B of A. I live in FL, and someone used my card in NJ. Bank of America shut my card off right after it happened, sent me an email, text message, and gave me a phone call letting me know they'd detected fraud. When I called them back, they gave me the option to turn the card back on (in case I'd jumped on a plane to NJ) or initiate a fraud investigation.
I think the fraud algorithm they use is pretty good, they found it right away. Fortunately it was only a $4.80 "test" charge. But they prevented any more money from coming out, and got the 4.80 back to me within 48 business hours.
Yeah, I use CIBC (Canadian) and they seem to take similar measures. There have been probably half a dozen times over just as many years where they have temporarily disabled my card and immediately called me due to suspicious activity. In each of these case, it was (thankfully) a false positive due to me traveling at the time, but it is somewhat reassuring to know that something is watching, just in case.
Thankfully, you can also call to let them beforehand that you are out of the country so you can hopefully avoid the card being disabled when you try to pay for dinner in that fancy restaurant.