Every person who is a qualified elector of the state of Idaho may sign a petition for the referendum or for the initiative for any measure which he is legally entitled to vote upon. Any person signing any name other than his own to any petition, or knowingly signing his name more than once for the same measure at one election, or who is not at the time of signing the same a legal voter of this state, or any officer or person wilfully violating any provision of this statute, shall, upon conviction thereof be punished by a fine not exceeding five thousand dollars ($5,000) or by imprisonment in the penitentiary not exceeding two (2) years, or by both such fine and imprisonment, in the discretion of the court before which such conviction shall be had. Any such wrongful signatures are null and void and shall not be counted as a qualified signature. Any person circulating a petition, who knows, or who in the exercise of reasonable care should know, that a signature is forged and who shall thereafter fail to strike through and thereby void such signature, and any person in a position of supervision of such person who suffers or permits a forged signature to remain on a petition shall pay a fine of not less than one thousand dollars ($1,000) for each such signature.