Early in my career, I was looking through our Apache logs when I noticed something I never thought I’d see: HTTP GET requests for the .js file I wrote to power our company’s amortization calculator... but with an HTTP REFERER of our competitor’s website domain.
I confirmed that yes, they were script src’ing to our js file.
Starting that evening, requests for our old js file caused an alert box to appear which said “You are now being redirected to our new site and calculator” and it redirected to our site.
I wish I could have been a fly on the wall at our competitor’s site to see the bewildered look on their faces. I almost feel bad for what must have been the junior developer who included our file.