A Woman Drinking From A Man's Cup

Recently, I encountered what is either a new chumra, or a strange new twist on a segula. It was at a separate-seating sheva-brachot, and the chassan's wine and kallah's wine was being distributed.

The cup came to a single girl and she asked someone, concernedly, whether a man had drank from it, for if so, she did not wish to drink from it. She was assured by the other party that only women had drunk from it.

What exactly was the concern here?

There are three possibilities I can think of.

#1: There is a harchaka that a woman should not drink directly from her husband's cup when she is a niddah. Since this girl was unmarried, she never went to the mikveh, and thus had the halachic status of niddah. Therefore, she did not wish to drink from the same cup as a man.

This is silly, of course, because it is specifically a harchaka for a woman and her husband, so they they do not forget and progress to other things. It is most assuredly not for women in general. And especially where here, she did not even know whether a man had imbibed from this cup -- who would she become overly familiar with?

#2: Perhaps there is some injunction in general that some have adopted, not to have mixed drinking (just as there is separate seating), to prevent mingling of the sexes, which would be defined as drinking from the same cup. I've never heard of this before, but it is possible.

#3: There were two cups in play, and this is a segulah for finding a mate. Perhaps her fear was that if she drank from the cup for the men, she would be matched with a woman rather than with a man.

:)

In any case, I am of the opinion that this is an entirely unnecessary, silly practice.