The provisions of this chapter shall not apply to trailers parked on the grounds of the Frederick County Agricultural Society or to carnivals, when the term of stay does not exceed one week; except, that the occupants shall comply with any health regulations that may be enforced by the deputy state health officer of the county; provided, that the Frederick County Agricultural Society or the sponsor of a carnival shall collect a fee of two dollars and fifty cents ($2.50) for each unit per week or fraction thereof and remit the same to the city treasurer. (Code 1953, § 20.2.)