The issue here is of course that the harasser already knew where to find his victim and already had her contact details.
Yes, in theory, she and her husband could have picked up and moved, changed their names (and their child’s), rented an apartment, never used the internet for anything, never contacted any of their previous friends or work colleagues, had no contact whatsoever with their relatives, changed their fields of work completely and basically become completely different people. /s
Ideally, they’d split up and put the child up for adoption too. /s