You may want to ask an attorney to draft verbiage that you can add to your listing agreements that will protect you from this unlikely and unfortunate event. 

Maybe something to the tune of "seller hereby agrees that upon closing of his/her property described within, that seller will unilaterally grant rights to the closing attorney to distribute Realtor commissions without any delays. This request will supersede any agreements or requests made after the signing of this agreement."

DO NOT USE THAT VERBIAGE ABOVE, YOU MUST GET THE VERBIAGE FROM A NC LICENSED REAL ESTATE ATTORNEY.