Amex issues A gift card which is in fact a pre-paid credit card. If an AMEX gift card is processed without the tip included, the transaction will be authorized. If you then add A tip to this transaction upon batching the [i:3narttkk][b:3narttkk]entire[/b:3narttkk][/i:3narttkk] transaction will be [b:3narttkk][i:3narttkk]DECLINED[/i:3narttkk][/b:3narttkk]!!! Be sure to add tip prior to swiping the card, as you would with A normal Gift Card. This is an issue with AMEX and additional info can be found at their website.