倘若大清邮局(无论上海还是其他地方)根本不知道欠资一事,那今天应有很多寄美国走日客邮欠资的混贴明信片存世才对。但实际情况却是很罕见。
倘若能发现有其它贴足邮资的(more than 4 cents, e,g 10 cents)寄美国走日客邮片存在,那就可以证明当时寄信人脑子是进水了,因为No one with a right mind would mail a postcard to oversea location at the same postage of an international letter.