I found this in a 1966 magazine at work:
"Lady's First"
Q: Why do ladies always go first? (From a teen-age boy)
A: It is simply a matter of courtesy. You may be surprised to learn that ladies do not always go first, however. It is a common mistake on the part of men to know when to go first themselves under certain circumstances. These are:
On the steps of a train in order to help the lady alight;
Through the corrider of a train, so taht he may open heavy doors;
Out of a taxi, so he may assist her in alighting;
Through a crowd, so he may make a path for her;
In a restaurant when there is no headwaiter to guide them to their seats;
Down stairs, to break her fall if she trips;
Into the theatre, if there is no usher;
Into a darkened room or any other place where a lady entering alone might have difficulty or encounter danger.
