Elsewhere on Wall Street, strikes are on the tips of tongues. A Bloomberg News analysis found that S&P 500 executives and analysts talked about unions on earnings calls more this year than any other on record, according to data going back two decades. They, too, have been quick to assure investors that the labor uptick is no big deal. Caesars Entertainment Inc. CEO Thomas Reeg told analysts that a recently settled contract with Necada's Culinary Union is "going to be the largest increase that our employees have seen" in four decades.

"That's well deserved. It's anticipated in our business model," he said.

Such comments, arguably made to calm antsy investors, are partly bluster. But they also reflect the changed balance of forces in the United States. Were the public not so pro-labor, and were the labor market not so tight, one might hear management rail against greedy unions and entitled workers. But those workers were, in the not so distant past, lauded as frontline heroes, and fewer unemployed people are lining up to replace them. Compromise in the face of a well-organized strike may be the safest line for the boardroom.