Trademark protection is about good-faith dealing with your fellow man. It’s about standing behind your product. Backing up your boasts, and differentiating your business without stepping on others or undeservedly riding coattails. We’re human beings, not Ferengi. Capitalism doesn’t have to be a dog park.
Call me a goody-two-shoes, but I feel like actual intent to benefit from the popularity of a name or brand, knowing its similarity to another mark, should be the determining factor of infringement, not whether or not precedent says you can get away with it. Just in general. All I’m saying is, “don’t be a jerk.” Protecting being a jerk is not what laws are for. You know what you’re doing, if you label brown soda you made in your toilet “CACA-Cola.”
Likewise, if you’ve got a popular mark, whether legitimately applied to a worthy product or not, I think you have a duty to not so-egregiously apply it to diverse and unrelated products and services, in order to be fair to the rest of the players in public commerce. Again, if you need a rule to live by, and you don’t know the applicable legal standard, just default to, “don’t be a jerk.”