No, nothing unyeshivish about hadar.. but tiferes runs a shtick more greasy! as one person said who actually went there to check them both out..
In Hadar the girls had their top button open (totally tnius of course), in tiferes, they had their top button done up.. (and in a 3rd place which we shall not mention, there were 2 buttons open!)
or you could use the example of a womans snood.. how low down she wears it.. (except that noone in seminary is wearing snoods yet!)