I see, but of course but no one is judging her for her appearance.
The fact is that we are each responsible for our own sins. If a man lusts because of what a woman is wearing then he needs to look away. The fault lies with him, not with the woman.
Further, who makes the call? Some men might not lust after seeing an attractive woman in a pants suit but would lust after that same woman in a bikini. Others might lust lust after any woman wearing anything short of a burqa. Who makes the call?
When a person repents of his sin, that is to cleanse his hands of the sin that had formerly gripped him (James 4:8), he removes all sources of temptation - he throws away his magazines, cancels online accounts etc. .. why does he do this? Just as a smoker who is becoming a non-smoker knows, that it takes only one cigarette to get hooked again. So they remove all opportunity to fall back on to that destructive path.
So when it comes and sits right next to him, (in a place of sanctuary), that needs to be addressed. A person's pride in appearance cannot be allowed to give the devil a foothold and open the door to many problems for someone who is genuinely making an effort to be renewed in his thinking (James 5:20, Romans 12:2).
It only takes one moment of thought for his habit to be re-ignited, because he has already found some sort of gratification in that thought that he has long since forgotten - and then that weakness can be gradually worked into a temptation that leads to action, and that in turn leads to death as James 1:14-15 describes (where they have again fallen into the degenerate mindset, they argue "it's not my fault, it's a natural thing - God, how can you do this to me!!!").
Furthermore, the spirit that possesses a girl to dress that way in the first place, of course it is aware that boys respond in this way. She thinks it's cute in a way, so she has some sort pity on him. Seeing she sits there, mindful that boys are thinking of her in that way, if they happen to glance at her to see "who is this new person?", the thought on her mind is "yeah I know, you think I'm hot, huh?". She probably has guys looking at her that way everywhere she goes. That non-verbal communication is how the idea gets planted, the accuser has spoken to the boy, the boy has been reminded that indeed he has been fractured, and so he receives the due penalty for his perversion.
Sofaras where does the line get drawn.. that's a personal thing. It really does depend upon how much one has exercised his desire and found out how focusing thought to admire various physical appearances can have corresponding impact upon his chemistry.
Keep one's eyes on the person that wears the flesh, that is to live in the spirit so as to not fulfil the desires of the flesh (Galatians 5:16). Picking one's mind up out of the gutter. Yet, the whole world lies itself down into the power of the wicked one, and his desires is what it desires to do. So just as 1 Peter 4:4 describes, it actually has expectation in it's heart that everyone must be thinking lustfully when they look at the girl.
Personally, it isn't for me that a person tempts me to see them that way when they dress that way, but that they have already decided to accuse me of seeing them that way before I even know that they are there. That false accusation, that just because a man looks at her with a smile on his face, she thinks in response "ugh, gross".. seriously. I am saying, think carefully of each one's individual responsibility toward what is holy and good - what kind of world do you want it to be?
To the pure all things are pure; but to those who are defiled and unbelieving, nothing is pure. Both their mind and conscience are defiled.
Titus 1:15
.. and that leads back to the short discussion I had two pages back, about how Eve became defiled. We are not born defiled, but James 1:14-15 observes that when we are dragged out (dragged out from where?) by our desires, then sin is conceived.