She definitely doesn’t deserve this.
That being said, addressing him directly and with power, but calmly could be an option. Don’t do it alone, but approaching a little and saying “I’ve noticed you at least 5 separate times and it’s creeping me out, please stay away from me.”
He’ll most likely deny it or try to play it off, maybe even insult her, but standing her ground and saying “I don’t believe you, I’m only asking nicely this time, there’s no next time without the cops” and then walking away.
No insulting, no debating. It’s a notice.
And of course, actually follow through, you see him again then call the non-emergency line and make a report. He can lie all he wants, once somebody has 2 or 3 police reports to prove he keeps showing up where they are then they can get a TRO within days.
It’s not fair that she has to essentially make this her part time job, but it can be an effective option that doesn’t have the side effects of making her look or feel at fault.
It’s incredibly frustrating that the one being wronged has to keep their composure