It will probably just annoy her.
Seriously, what's the point? If she can't be bothered to see you for 15 minutes, what do you hope to gain by stopping by with seemingly no purpose?
You may not have much to lose, but you probably have about as much to gain on this one. A better approach might be to see if you can get some contact information from her and leave it at that.
Not a good strategy. If a person says they are busy, then they are or they just aren't interested in meeting with someone. In most business settings (contrary to the "Trump Methodology") aggressiveness and/or intrusiveness is not acceptable.
The BEST way to annoy any hiring manager or recruiter is to show up unannounced and demand a meeting. You may get a few minutes, but you will NEVER get a job.