No person shall willfully or maliciously remove, destroy, or alter the number of the frame of any bicycle licensed pursuant to this chapter. No person shall remove, destroy, or alter any license or registration card during the time which such license or registration card is valid; provided, however, nothing in this chapter shall prohibit the director of finance, or other such person as may be designated by the council, from stamping numbers on the frames of bicycles on which no serial number can be found or on which such number is illegible or insufficient for identification purposes. (Ord. 396 § 1; Ord. 202 § 1. 2002 Code § 3-5.7).