To them you'll likely seem like an overzealous geek that shouldn't mess with their business website. I've experienced this before myself and it's not particularly a good position to be in.
Their site has most likely been technically abandoned, i.e. no one capable is in charge anymore.
It'd be best to talk to the owner, show them your "hack" (change it to cats on your phone and let them verify in their browser) and offer them to fix it for free.
That's how one does these things in our small country. ;-)