S.C. Code Ann. § 34-28-630: Powers of attorney on deposit accounts.

Any association or federal association may continue to recognize the authority of an attorney-in-fact authorized in writing to manage or to make withdrawals either in whole or in part from any deposit account to an account holder, whether minor or adult, until it receives written notice or is on actual notice of the revocation of his authority. For the purposes of this section, written notice of the death or adjudication of incompetency of the account holder constitutes written notice of revocation of the authority of his attorney. No association is liable for damages, penalty, or tax by reason of any payment made pursuant to this section.