[QUOTE=garygnu]
The cards in question are combo debit/credit cards, and terms for usage are ambiguous. When used as a credit card, they have a low daily limit that is NOT checked against the balance of the account that it’s connected with.The transaction goes through Visa (or whoever) as a middle-man.
These same cards can also be used as ATM/debit cards, but require a PIN to be entered. When used in this way, it IS directly checked against the checking account and directly debited.
[/QUOTE]
This is not correct. Regardless of which function is used, the account is queried for whether or not the balance exceeds the proposed transaction. Thus, if your checking account has, say, $45.56 in it, and you go to pay at the pump using the “credit” function of the card (assume for the purpose of this discussion it uses the VISA system), then you won’t be able to pump more than $45.56 in gasoline.
However, the funds are not immeditely debited from your account, as they would be if you used the “debit” function of the card. Instead, a hold is normally placed on the account for the amount you charge. If you are at a store, and you “charge” $25.56, your accunt will show a balance of $45.56, but a usable balance of only $20.00.
The pay at the pump feature, however, usually gets processed slightly differently. The pump queries the system for available balance, up to the limit imposed by VISA or MasterCard (locally, I’ve seen $50 for the one and $75 for the other). At that time, it puts in place-holder transaction of $1. You complete the purchase of the gasoline for $25.56, and the system then runs the transaction through the VISA/MasterCard system like it would any other credit transaction. When it does, the place-holder gets replaced with the actual transaction. So, after you have pumped, your account would be $45.56 with a usable balance of $44.56. Two or three days later, the balance would drop to $20.00, assuming you haven’t put in additional transactions.
Needless to say, this can cause you problems!!! If you subsequently attempt to use the “charge” feature to charge a $35.00 item, you will be successful, despite the fact that the two charges are a total of $60.56! When the gasoline purchase is cleared through the system by VISA/MasterCard, you will end up having over-drawn your account, unless you have managed a deposit in the interim. VERY annoying if you are running at the limit of your account, for whatever reason, and not keeping a close running tally of funds.