About 20 years ago I used my credit card in a restaurant in Tampa. The next day, or the day after that, I got a phone call from VISA security asking if I had bought $1,000 worth of stereo equipment in New York City the day before. I told them no and they said, "We didn't think so". They cancelled that card and sent me a new one and the stereo equipment never showed up on my bill.
Current credit card fraud detection algorithms are VERY sophisticated. They track your spending patterns and look for suspicious deviations. They also track point-of-sale purchase locations and look for unusual deviations and distance-over-time jumps. It is very impressive and scary.
15 years ago,I was living in Maryland at time. Used my Amex in restaurant I’d never been to.
2 days later got call from AMEX asking if I had purchased 3 surf boards in Toronto Canada.
Lots servers with card skimmers around even then.