I've heard stories that Heinz is so defensive of their brand that they send out "Ketchup Inspectors" to make sure restaurants aren't refilling Heinz bottles with lesser ketchup. This is the only somewhat legitimate source that I could find: http://www.freerepublic.com/focus/f-news/1067133/posts
I don't even like ketchup and I could pick out Heinz in a blind taste test.