How could the bank see this after the cardholder left the store, if the transaction were disputed, unless the proper procedure was followed? The magnetic stripe on a Chip card can be cloned just the same as the magnetic strip on a swipe card. This is a strategy which prevents the cashier from manually bypassing the chip and using the magstripe.
Yes, but the mag stripe will have a flag set if it is a chipped card telling the cashier to read the chip instead. A straight clone of the card won't work because an EMV capable terminal will recognize that the cloned card is supposed to have a chip. Now, it might be possible to clone the number, change the checksums, etc., but I think there would be lower hanging fruit out there.
In short, the EMV terminal will correct the cashier if the card is EMV and the cashier swipes the card without first attempting the chip.