Over the years there have been several 'issues' that have cropped up of 'questionable' use.
Does anybody remember the company that had a cover format very similar to the Core Rulebooks? In addition, they were even being marketed as 'the other core rulebooks' or something similar. I don't want to name names because it isn't important.
Anyway, WotC felt the similarities were too similar and that there was confusion between the products. Looking at them side by side in a store, I can see where the concern is legitimate.
So if a [blank]craft came out, I am not sure it would be a clear example of riding the coattails of another publisher. However, if that book also used font and layout that were very similar I could see there being legitimate concern.
As a consumer, I very much appreciate the RPG market trying to maintain friendly competitin rather than bitter aggression toward each other.
What impact does friendly competion have on me? Well given the number of freelancers that work for multiple companies I think there is a lot of relevance to me. Phil is a good example I think. Since he started the thread, I will abuse him somewhat.
Phil has worked with Steve Jackson games, I am pretty suer he has done some freelancing on Star Wars Mini battles, he has worked with Mystic Eye Games, Green Ronin, Bad Axe Games, etc. I know he has done some of this work via Ronin Arts, but there are freelance author credits in there as well. Ronin arts also distributes projects from other freelancers that have worked with different companies. Obviously it is in Phil's interests not to upset these companies. But it is also in my interests. I want to see the niche products that a larger company might not want to take the risk on.
With healthy, friendly working relationships, the consumers get to see the efforts of some authors across multiple companies. This is important because this market is small enough that it might not be possible for a company to keep an author onboard full time. They can freelance it out for project X or Y.
Once the relationships shift to aggressive and decidely unfriendly, you start entering turf battles. Author A can't work for Company W without risking the wrath of Company Z. But Company Z doesn't have a project for Author A right now, so Author A can't afford to eat. Of course, in a few months, Company W won't have a project either and Author A won't be eating at that time because Company Z is in a tizzy. So Author A decides to go back to being Worker Bee 2478 for non-gaming Corporation J and now we don't see any new products being written.
These issues can, of course, crop up right now anyway. Maybe they do. But there are a lot of freelancers that have moved between projects and companies.
Now if a company refuses to let another company use material, they have no legal recourse. Assuming it is OGC that is being used. But it would still be best to avoid anything that might be construed as infringing on another company's trademarks or IP. Why would it need to be called [blank]craft? Just come up with a new name and a clear format.