That meant no Jews, Blacks, or any other undesirable group that management did not want to hobnob with their elite, very white guests, should not even dream of trying to stay there. Ethnic groups were not the only ones to be discriminated against. If she got married, she lost her job. It's as simple as that. It would be interesting to know just what the town fathers who decided this meant.
Stereotypes show up in many ways.
At the turn of the century, it became extremely fashionable and accepted to send Vinegar Valentines or penny dreadfuls, because they cost a penny. Actually, they had started well before then and were the catalyst for changing how part of the postal service worked. Previously, the person receiving the mail paid for the postage, not the sender. There were all types of personalities and professions that were ripe for this type of abuse. Just as lawyer bashing is popular today, it was just as popular at the turn of the century.