The whole commercial... the two women - a blonde and a brunette - go into the bathroom together. They check their make-up in the mirror and then, without saying a word, pull off their wigs and switch. The blonde becomes a brunette and vice versa. Then they giggle and leave the bathroom together.

I'm not sure if they're trying to fool their dates, doing a little covert partner swapping, or what. But I think I like your interpretation better. ;-D