There are plenty of circumstances where professional attire can be a little revealing if a person is leaning in a particular way, and creeps position themselves to catch a glimpse. The only way to stop this is to "cover up" in a way more reminiscent of Riyadh than Eugene. Or teach lechers simple rules about what is considered normal behavior.

On the other hand, maybe she wore a plunging neckline. In that case, it may be hard not to casually glance... after all, people notice things in their field of view! But to stare would be creepy.

Taking a picture of someone without consent is rude in many situation... a picture of cleavage is even worse as it makes it clear the picture was for sexual purposes (despite the lame disclaimer of a necklace).