When performing a booking verification, the following cases are the most common reasons for a booking to be identified as "high-risk":
- The card does not hold sufficient funds.
- The bank declined the card validity.
- The card will expire before the check-in.
- The card is a prepaid card.
- The country of card issuance is different from the country in which the booking was made.
Receiving a high-risk booking does not mean the client is a fraudster.
It rather means that IF the client is a fraudster or a no-show, it is highly unlikely you will be able to bill the card. So, to be on the safe side, you should contact your client and ask for a valid card.