Incidents of racial bias have hit major brands including Uber, Starbucks and Airbnb. Now they are cropping up at hotels, unsettling guests, spreading via social media with the hashtag #TravelingWhileBlack, and leading some in the travel industry to revisit diversity training.

In May, the Washington Post ran an article about a hotel clerk at the Country Inn & Suites by Radisson in Newport News, Va., calling a black guest a "monkey." The employee was fired, the hotel general manager said.

In June, Carle Wheeler, an African-American software engineer from Dallas who stayed at the Westin Pasadena in California, posted a Facebook video showing a white man asking her and her daughter if they had bathed before swimming in the pool. The video shows the hotel manager dismissing the man while encouraging the distraught family to "enjoy the pool." Wheeler felt that the manager should have confronted him sooner, according to the Post.

And in July, an African-American man and his son returned to their room at the Art Ovation Hotel in Sarasota, Fla., part of Marriott's Autograph Collection, to find a racist note in their room. The hotel later determined it had been left by a previous guest and did not target the family.

While the hotel companies expressed zero tolerance for bias from either employees or guests, the episodes did not elicit apologies from top corporate executives.

"The incidents did not seem to create some new wave of sensitivity training or messaging," said Bjorn Hanson, a professor in the Jonathan Tisch Center for Hospitality and Tourism at New York University, who explained that hotel employee training in diversity is common in an industry built upon welcoming people from around the world.

"As a person in the guest-facing role, you will experience the opportunity to welcome people of different backgrounds, religions, customs and sexual orientations," he said. "It's almost part of the job description to serve different backgrounds."

But diversity training varies. Marriott mandates inclusion training for all employees at the hotels it manages. But when it comes to franchised hotels or those more loosely bound to Marriott, such as the Art Ovation Hotel, the company says it can only suggest training and make the tools available to franchisees. The Art Ovation Hotel said all of its employees undergo anti-discrimination training.

After the episode at the Country Inn & Suites, which is also a franchise, employees were "retrained on code-of-conduct policies related to expectations and guiding principles for appropriate workplace behavior."

"Isolated incidents like this one are very unfortunate, but provide an opportunity for the company to reinforce the importance of our guest service expectations with our franchisees," wrote Laura Langemo, a spokeswoman for Radisson Hotel Group, in an e-mail.

Instilling racial and cultural sensitivity is difficult because it is generally not reviewed or evaluated on the job the way more quantifiable tasks such as computer skills are, said Jamie Perry, an assistant professor of human resource management in the School of Hotel Administration at the Cornell S.C. Johnson College of Business.

"That basic level of awareness, that these people look different from me or are different culturally, is a first step in any successful diversity program, helping employees be aware of differences," she said. "A lot of things we're seeing in the news get at that underlying implicit bias that people have and are not aware of until it's, 'Omigod, that came out of my mouth.' Training creates a dialogue about differences."

Not a surprise to all

There may still not be enough of it, however, as travel experts expressed dismay, but not surprise, at the news.

"In the black community as a whole, we've known this has been going on for a long time, but camera phones and social media are finally showing it," said Evita Turquoise Robinson, founder and chief executive of Nomadness Travel Tribe. "This is something we've always been hyper-aware of, and travel is a very specific context. Black travelers choose places to go based on how we feel we'll be received in that place. It becomes a safety issue."

As a journalist and the host of two digital shows on the Travel Channel, Oneika Raymond, who is black, has visited more than 100 countries and experienced a few stinging encounters with racial bias on the road. In those situations, she advises speaking up and keeping records.

"If I encounter racial discrimination, I'm going to say something about it, but I always keep my cool," she said. "Address them head on, calmly, with a level head if possible and escalate it to the people who matter, whether that's a head office or manager. I always write things down."

Carle Wheeler said she received an apology and an assurance that Westin Pasadena employees would undergo "unconscious bias training." The company confirms that they did. The hotel also deducted one night from her hotel bill. But Wheeler, who called the episode "traumatizing," said she felt the apology was only elicited by the attention it received.

"This experience absolutely changes the way I feel about the Westin as an entire brand," she wrote via Facebook Messenger. "Had this incident been handled in a timely and satisfactory manner ... then maybe I would see it as an isolated incident."

Travel for African-Americans has been a fraught experience for generations. From 1936 to 1967, "The Negro Motorist Green Book," founded by Victor H. Green, a New York postal worker, identified welcoming places for African-Americans that included hotels, restaurants, gas stations and services, according to Candacy Taylor, an author and photographer who is documenting Green Book sites.

"This doesn't mean Westin or Starbucks or Airbnb are racist companies," Taylor said. "We keep pointing the finger and that person is fired, and there should be some action, but we keep missing the deeper DNA of where this comes from. We've got to get to a deeper level where black people feel safe as Americans like everyone else, which is what the 'Green Book' was trying to do."