Yep. The trademark litmus test is whether or not there is a "likelihood of confusion" with the business that owns/claims said trademark. So if I was to create a

Yep. The trademark litmus test is whether or not there is a "likelihood of confusion" with the business that owns/claims said trademark. So if I was to create and sell a t-shirt with, say, a photo of Mickey Mouse on it, Disney could sue me and claim I was infringing upon their trademark (the mouse), and causing customers to think that my shirts were from Disney. So it doesn't have to be within the same type of business - it just has to be likely to cause confusion. (In the case of UPS brown, it would make sense that it can't be used by another delivery service on their trucks, given how prominent it is to the UPS brand. But for a grocery store, for instance, that color wouldn't cause confusion.)