I work in accounting and am not an attorney; [MENTION=38651]merlinextraligh[/MENTION] can feel free to correct me.

The company I work for is an agricultural equipment manufacturer, and I think the issue here lies with how the color or combination of colors is used. For instance, we are not allowed to use the colors green and yellow together on any of our products. John Deere has explicitly told us so. Our own attorneys have told us this: We can use green, we can use yellow, we cannot not use them together on any agricultural equipment. If we were making, say, garage doors or coffee cups, we could use whatever color combos we want (as long as it doesn't imply John Deere). The same way with the aforementioned UPS. I can make whatever I want in UPS brown and yellow, but I would not be able to start a freight/courier business using those colors.

We have even lost sales because of this. Many of our customers want our equipment in green and yellow to match their John Deere tractors and combines, and are baffled because we won't offer it to them. We have offered to pay licensing fees, but Deere isn't interested. This also goes for any shade of green and yellow; it isn't a matter of offering a similar (but different) shade and calling it good, it covers any use of those two colors together. What we ended up doing was to continue using green as the dominant color (the exact same shade of green as JD, by the way), and replaced the yellow with another neutral color. This way the equipment will at least not clash.

As much as I don't want to, I understand their argument. They've spent years building up a brand and reputation with those colors. Someone else using them implies an association and would become free advertising. At the same time, producing faulty or sub par equipment could be a detriment to them if someone associated the two.