Comment 19(e)(1)(vi)-6, with relevant text highlighted:
Additional information on written list. The creditor may include a statement on the written list that the listing of a settlement service provider does not constitute an endorsement of that service provider. The creditor may also identify on the written list providers of services for which the consumer is not permitted to shop, provided that the creditor clearly and conspicuously distinguishes those services from the services for which the consumer is permitted to shop. This may be accomplished by placing the services under different headings. For example, if the list provided pursuant to § 1026.19(e)(1)(vi)(C) identifies providers of pest inspections and surveys, but the consumer may select a provider, other than those identified on the list, for only the survey, then the list must specifically inform the consumer that the consumer is permitted to select a provider, other than a provider identified on the list, for only the survey.
That is the only reference to the option. I have never yet heard of a lender that has used it. The reasons are obvious.