Writers for newspapers should be especially careful in their word selection, because their work is out in the open for the public to see and criticize.
A recent story in the Waynesville, NC Mountaineer illustrates the point. The headline reads: "Grower rift leads to duel markets." This writer needed to check his dictionary, for he has a problem here with “homophones:” words like “duel” and “dual” that sound alike but have very different meanings.
Duel is a noun, defined as “A prearranged combat between two persons…” Markets cannot have a “duel,” nor can you have a noun modifying another noun, as in this case.
However, you could certainly have “dual” markets.
The writer could have used the present participle “dueling” which would have been correct, for that is a verbal adjective which can modify a noun. But he didn’t, so his error is on the front page for everyone to see.