you brought it on yourself miss twiddle

From Emily Post's first edition:

Among the few occasions when it is acceptable to put more than one guest per/room:

On an occasion such as a wedding, a ball, or an intercollegiate athletic event, young people don’t mind for one night (that is spent for the greater part “up”) how many are doubled; and house room is limited merely to cot space, sofas, and even the billiard table.

About young girls (nb: this means, according to Ms Post, under 30 if unmarried) being alone with men:

A young girl may not, even with her fiancé, lunch in a road house without a chaperon, or go on a journey that can by any possibility last over night. To go out with him in a small sail-boat sounds harmless enough, but might result in a questionable situation if they are becalmed, or if they are left helpless in a sudden fog.