I've only experienced the following holds on my credit card over the last ten years:
1. A $1 hold at gas stations that typically disappears within one day (if not sooner). When you use a self-serve pump, this presumably ensures that the credit card you are using is valid.
2. A $250 hold that is charged when checking into a hotel. This disappears as soon as I check out at the end of the hotel stay and the actual charge in the full amount of the hotel stay is applied to the card.
3. A similar $250-$300 hold charged by a rental car company when I pick up a rental car. This disappears when I return the car and the actual charge in the full amount of the rental is applied.
“It protects the merchant. “
The merchant has the option to NOT take the cards at all if they don’t want the risk.