Should You Really Buy Starbucks as Union Battle Heats Up?

Starbucks outlet staff walk out In protest after a fellow one employee gets fired.

The Starbucks Workers United said that Amato was fired for closing the store lobby without getting permission from the management.

The entire staff of a Starbucks store in Buffalo, New York, walked out mid-shift in protest of their fellow employee being fired without any credible reason.

Beloved coffee chain Starbucks (SBUX 1.48%) is facing a brewing conflict with its workers, who are slowly starting to unionize throughout the company.

It hasn't impacted business yet, but it could at some point. Here is why investors should remain cautious about the coffee giant's increasingly hot labor situation.

Time has flown by since the first Starbucks store voted to unionize last December.

Things have progressed; approximately 182 stores have successfully formed unions, 35 failed, and 96 votes remain open.

Starbucks has had a great decade, growing sales by an average of 9% annually and earnings per share (EPS) by nearly 15%.