How on earth is a pickup bobbin color trade markable anyways? It is a freaking color not a technology or innovation. I mean some some stupid reason it is, but that seems pretty lame.
You are confusing trademark and patent.
Trademarks are on
visual appearance (there are audio trademarks, but they are harder to get and rarer). If a company deems the appearance has value to the brand or product sales, they can trademark it. It's in Dimarzio's favor that the cream bobbins are purely
cosmetic, if the cream bobbins are essential to their operation, than they wouldn't be trademark-able (they would have been
patent-able...and patents expire).
Dimarzio has the trademark on the uncovered double cream HBs, a definitive look for the Super Distortion in the '70's and often associated with Dimarzio in the hard rock/metal world. People argue that Gibson had made double cream HBs back in '57, but those were all sold
covered, so the double-cream bobbins were not inherent to their marketing. Plus, unlike patents and copyrights, you can trademark previously existing features...even items that were a previous trademark was not renewed. Since Dimarzio still makes double-cream HBs, and has continuously for 40+ years, they should have an easy defense of this. I think the pickup maker is getting some poor advice, I would guess Dimarzio will take his business in a counter-suit to recover court fees.
Lollar had two strong points in a recent case against Rickenbacker over the horseshoe PU... 1) the horseshoe design is part of the operation of the PU and 2) Rickenbacker hadn't made a horseshoe PU for years. Ric ended up settling and licensing the design to Lollar. Neither of those points apply here. Also, lots of people note that Peavey and Mesa Boogie file and hold
patents on technology that may be pre-existing, making their patents invalid...that may be true (or not), they could lose in court (or not) but once again...that doesn't apply to trademarks.
I haven't seen any complaints with buying and selling raw cream bobbins (but I'm not in the business), Dimarzio doesn't have the trademark on cream bobbins...only double-cream, six pole HBs, it doesn't cover single bobbins, bladed PU's, square-bobbin HB's, 11-pole PUs or any other visually different designs. I never see other makers complain they can't get cream bobbins for zebra and reverse zebra PU's
BTW, Coke has won cases over their trademark shade of red.
I would just make pickups that say Fuck Dimarzio on them and see how long it would take for them to let me use cream.
I hate the cream/black pickups anyways. So it doesn't really matter to me. If I get a humbucker, I want it with a cover.
They own the trademark on "Dimarzio" as it applies to guitars and electronics, so they can sue over that too.