Most Helpful Guy
Normally, it's hot.
But if I can see her (old, worn out, ill-fitting, or not particularly clean) underwear the entire time, because her skirt is that short or because of how she acts, then, yeah, I might think 'trampy."
A party or a bar is a place where it is APPROPRIATE to be dressed up a little suggestively, and so that doesn't imply anything beyond trying to look good, unless you are actually ACTING suggestively, or wearing clothes (or wearing them in a way) that only a tramp would wear.
Those same clothes would send a very different message in another setting. You wouldn't wear stuff like that to work, for example, unless you're cocktail waitressing in a strip club.