It has happened with 4 different gals all at my place. Some have done it multiple times, but can't remember exactly how many instances there are exactly.
The first time I just thought that interesting how she's standing. The second time I was like "hmmm...that weird, shes doing the same thing".
The third and fourth time I was beginning to think this can't be all a coincidence. Has to be some sort of unconscious body language going on.
Every time we were talking about this and that, nothing special and these weren't my gf's, just friends of my spouse.
Can't say if this is a small sample or not...obviously big enough to peak my intrest in what this might mean.
I don't think asking them why they stand like that would be any good. They wouldn't know because body language is usually unconscious behavior. Anyway, I like it this way, so they wouldn't become self-conscious about it, so I can just observe how often it happens.