Section 50. Sections thirty-nine to forty-nine, inclusive, shall not apply to employees or agents of the commonwealth or of a city, town, district or regional school district who are acting in their capacity as such employees or agents or to any person requested to appear before any committee or commission of the general court by a majority of the members of such committee or commission; provided, that such person performs no other act to influence legislation; and provided further, that the name of such person be recorded in the official records of such committee or commission.