I personally like it, in most cases. Then again I'm a guy, so like other posters mentioned gender differences might play a role. Keep in mind though, that I believe if you're in a random public place, and someone approaches you, you should be wary because you don't know who that person is. If it's someone I know, even if I just barely know them, I feel much more comfortable. Better safe than sorry. Like I said though, most women aren't gonna approach random guys (although some do), and if a random guy approached me and was just trying to make conversation, I might have to end up telling him I'm straight.
The problem a lot of women have is that they're being hit on all the time, often by guys who are creeps. So you have to distinguish yourself as different from all of those other guys if you want to get anywhere. This isn't as tough as it looks provided you can present a good self-image, without coming across as braggy. In other words, don't tell unless asked.
But people I know approaching me, even if I've just met them once, I'm always open for it, unless you're intruding on me when I don't want to be around people, i.e. you knock on my door without calling first. An example of how I like to be approached by women: one time a girl was chasing after me and I walked slower so she could catch me.
Well, to get to the point in my long-winded post...I think you should go for it, just make sure you don't freak her out. If she does "diss" you even if you approach her the right way, it probably has more to do with her than you, i.e. she has a boyfriend, has problems, or just wants privacy.
Lastly, be careful with typing people right off. It's not really possible a lot of the time to type someone just by looking at them once from far away. I confused a good friend of mine, an ISFP, for an ENFJ (I guess introverted/extroverted feeling mix up). So, be careful not to label someone immediately.