The Wall Street Journal interviewed an array of current and former Starbucks staff and managers, who said their training didn’t address the question, and were unaware of a written policy on non-paying customers. Instead, such judgments are generally left to store managers or individual store policies.

That ambiguity is, in part, baked in to Starbucks’ business model and mission. Far from just selling coffee, the chain was conceived by former CEO Howard Schulz as a “third place” between home and work, modeled on Italian cafes where patrons would hang out for hours, conversing or just relaxing. It would be hard to create the sense of community Starbucks is premised on if staff were tasked with forcing everyone in the store to buy a set amount of coffee or scones.

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On the other hand, staffers speaking to the Journal pointed out that being too lenient with non-paying guests can lead some to take full advantage, potentially crowding out paying customers.

Flexible policies allow managers to exercise their own judgment over that double-edged dynamic. But they also, as the Philadelphia incident showed, open a wide lane for Starbucks staff to display their own biases – unconscious or otherwise, racial or otherwise. One sort of person ‘waiting for a friend’ without buying anything may seem innocuous, while another is seen as a threat worthy of a police call.

Starbucks has more or less owned up to this failing already. In a statement after the Philadelphia incident, CEO Kevin Johnson wrote that “creating an environment that is both safe and welcoming for everyone is paramount for every store,” but that in Philadelphia, “our practices and training led to a bad outcome.” Starbucks will close its stores for part of the day on May 29^th for a company-wide training on racial bias, which could make at least some headway in navigating the very fine line the company has set for itself.