Sam doesn't know why, or she did it for Sam subconciously without rationalising why, or admitting it to herself, or both? Either way, I've known prostitutes her age who wouldn't have gone to a bar dressed like that while they were working, let alone to see a teen band & at night FFS. This outfit positively screams, "I'm desperate & I demand attention, look at me," or maybe, "Why is everyone staring? Oh me, oh my, am I really gorgeous? I never guessed." As Monty Python would have put it, "It's all getting extremely silly."