A license holder or an employee of a license holder who is charged with a violation of § 6–304 of this article: shall receive a summons to appear in court on a certain day to answer the charges placed against the license holder or employee; and may not be required to post bail pending trial in any court in the State. A license holder or an employee of a license holder may not be found guilty of a violation of § 6–304 of this article if: the license holder or employee establishes to the satisfaction of the finder of fact that the license holder or employee used due caution to establish that the individual was not under the age of 21 years; and the individual was not a resident of the State. The granting of probation before judgment to a license holder or employee of the license holder for a violation of § 6–304 of this article does not bar the Board from proceeding administratively against the license holder for the violation.