一點信息，

不會回答你的問題,but at least you know, since I own my own business, I was told that if sometimes you take the credit card charge over the phone and then imprint the copy of the card, even the cardholder dispute the charge, it will still be valid, or basically if we slide the card by our terminal, then basically no charge back.

it doesn't sound reasonable by thinking about signature, but that's what the guy who install the credit card termimal told me.