No bond shall be required to issue a preliminary injunction or special injunction sought by the district attorney or the solicitor for the county or municipality. A bond in an amount fixed and with security approved by the court may be required to issue a preliminary injunction or special injunction when the plaintiff is not the district attorney, the Attorney General or a solicitor for the county or municipality. Where such relief is issued after an evidentiary hearing at which witnesses are subject to cross examination, the court shall not require a bond in excess of $500.