I know, right? Even if we're assuming that this rule only applies to close relationships... what if she (I've seen a he too, just not nearly as often) has a female friend who thought she was straight and then later came out as a lesbian, does all the time they spent pre-coming out retroactively become a betrayal? What about demi people who don't have a gender preference - "you can be friends with this demi person, but you're only allowed to get THIS close"? And I'm guessing that all questioning people are out automatically? "Sorry Jane, since you're not sure if you're straight or not, I can't be friends with you. Call me if you decide you're straight." (I know I'm nitpicking here, but honestly, the only way this rule even works is if you don't think about it too much.)