The Incredible Honeymoon by Edith Nesbit

ONLY those who have gone through the ceremony of a mock marriage, from the gentlest motives, and have soothed the solicitude of a beloved and invalid aunt by the gift of the marriage certificate thus obtained, can have any idea of the minor difficulties which beset the path of the really unselfish. Had the ceremony been one in which either party was deceived as to its real nature the sequent embarrassments would have been far less. The first and greatest was the question of names. The persons mentioned in the certificate now bedewed by the joyful tears of the invalid aunt, and scorched by the fierce fires of a first-class family row, were committed, so far as the family and the world knew, to a wedding-journey. That is to say, Mr. and Mrs. Basingstoke, after posting the certificate, were to proceed on their honeymoon. But cold mock marriages claim no honeymoon.

So far the only explanation of the relations of the now mockly married had been made to Mr. Schultz across the peaches in the sunned and shadowy arbor at Tunbridge Wells. To Mr. Schultz the two were brother and sister. To travel as Mr. and Mrs. Basingstoke presented difficulties almost insurmountable -- to pursue their wanderings as Mr. and Miss Basingstoke involved bother about letters and the constant risk of explanations to any of the friends and relations of either across whose path fate might be spiteful enough to drive them. Because, of course, your friends and relations know how many brothers and sisters you have and what they look like, and those sort of people never forget. You could never persuade them that the young man with whom you were traveling was a brother whom they had overlooked or forgotten.