I have always wanted to start a thread about this, but I usually just stick to lurking. I have always been quite shocked by these posts. I cannot imagine even considering doing such a thing. That situation would be totally akward for me.
I have actually vacationed and shared a room several times with male friends, but the friendship only thing was already clearly established.
I can't even bring myself to take the chance of sharing a room with another female who I don't know, never mind a male who is likely to have romantic expectations.