I know I've seen this answered before but can't find it. If a cardholder has their PIN written on a card and there is unauthorized use, can a financial institution refuse the dispute due to lack of responsibility by the card holder?

Nope.


Here's an older thread on the topic: https://www.bankersonline.com/forum/ubbthreads.php?ubb=showflat&Number=920226

From the Commentary to the regulation:

2. Consumer negligence. Negligence by the consumer cannot be used as the basis for imposing greater liability than is permissible under Regulation E. Thus, consumer behavior that may constitute negligence under state law, such as writing the PIN on a debit card or on a piece of paper kept with the card, does not affect the consumer's liability for unauthorized transfers.

While you may have to give them their money back, you don't have to give them the card back.

Fool me once, shame on you. Fool me twice, shame on me.