Does a mistake or inadvertence on the ballot box affect an election?

Dennen v. Jastro, supra, 23 Cal.App. 264, 267, 137 P. 1069, 1076, says: "A failure to comply with some technical direction of the statute, where due alone to mistake or inadvertence on the part of those whose duty it is to prepare and furnish the ballot, should not disfranchise the entire vote of the district and vitiate the election, unless it be made to appear that by reason of the irregularity the result was different from what it would otherwise have been, or that it prevented the voter from freely, fairly, and honestly expressing his choice . . . ."