Fraud Field Note: the small charge you don't recognize is not a mistake
People see a tiny charge they cannot place, a dollar here, a few cents there, and they wait. Maybe it is a billing error. Maybe it will sort itself out. That patience is exactly what the other side is counting on.
A small charge is not a glitch. It is a scout.
Before anyone runs up a stolen card, they test it. A cheap online purchase, a small donation, something that will not trip a limit or trigger a call. If it clears, the card is good and the real charges follow, usually fast, usually while you are still deciding whether the first one was worth worrying about. The people who lose the least treat the two dollar mystery like the warning it is and kill the card that day. The ones who lose the most gave it a week to see what would happen.
If you cannot name a charge, you do not owe it the benefit of the doubt. Small and strange is how the big one announces itself.
Have you ever caught a fraud early off one odd little charge, and what tipped you off?