info is power. social media is a great equalizer.
Chick being followed? no problem! If it's 2016 and she's paying $8 for a coffee, then without a doubt she has legions of white knights on her instatwitsnapface profiles.
Snap a pic of the creeper following you, and post it on all platforms. Ask your white knight males and drama queen females, to share and repost it. Within MINUTES, the creeper guy will be tagged, viewed 3000 times, and half of the people in that coffee shop will be looking up at him from whatever device they've been drooling on as they drink that over-sugared shit coffee. If creeper is dangerous, he is no longer anonymous, and knows if any chick is harassed within ten square miles, he'll be on the news cause they have his likeness now.
problem solved. Tell the guy he's about to go viral, now would be a good time to scram.