Uber has at times described itself as a ride-hailing service that "brings people together" - "a fun and social new way" to get people from place to place.
But some of Uber's passengers have perhaps become a bit too friendly in the back seat.
In its first guidelines specifically directed toward passengers, Uber wants people to remember: Don't have sex while riding in the car.
"That's no sexual conduct with drivers or fellow riders," it wrote in its new Community Guidelines, published Thursday.
It added: "No matter what."
The company's "no-sex rule" was one of many examples of poor behavior that could cause riders to lose access to Uber. The app-based car service instructed passengers not to touch or "flirt" with other people in the car - but neglected to expand on what constituted flirting.
"We all value our personal space and privacy," the company wrote. "It's OK to chat with other people in the car. But please don't comment on someone's appearance or ask whether they are single."
The reference to flirting brought to mind a study about racial and gender discrimination in ride-sharing companies published in October by the National Bureau of Economic Research. Researchers surmised that "a combination of flirtation and profiteering" may have led to what they found was a significant difference in trip time between male and female drivers. On average, female travelers were driven 5 per cent farther than males, given the same start and finish location.
In a statement, it reminded riders to follow the "universal truth" taught by all parents - treat people as you would like to be treated yourself. This means remembering not to leave trash in the car, not to vomit in the back seat after drinking too much alcohol or not to ask a driver to break the speed limit to get to a destination more quickly.
"This is important because when drivers use Uber they do more than simply drive: they're sharing their own car, their space, their time and a slice of who they are with passengers," the company wrote.
If it becomes aware of such problematic behavior, Uber will contact a passenger to investigate the claims, and depending on the nature of the incident, it could put a hold on a passenger's account.
There's a much more serious side to some of Uber's rules, as well.
"Any behavior involving violence, sexual misconduct, harassment, discrimination, or illegal activity while using Uber can result in the immediate loss of your account," it wrote.
Uber's guidance comes after a series of incidents - particularly those involving alleged sexual assaults - from the past year have at times shed a negative light on the company.
In January, an Uber driver was arrested in Georgia, charged with raping a woman who called him for a ride. Last month, an Uber driver in California was charged with sexual assault after allegedly raping an unconscious 17-year-old girl.
Also last month, Uber settled a lawsuit filed by two women who sought to hold the company responsible for alleged sexual assaults by drivers. The settlement came six months after a federal judge rejected the company's argument that it couldn't be blamed for sexual attacks by drivers, whom it classifies as contractors rather than employees.
After alleged attacks on passengers in India and South Africa, the car service rolled out a panic button in some vehicles in those countries.
But not all alleged attacks have been carried out by drivers. In November 2015, a corporate Taco Bell executive was taken into custody after viciously attacking an Uber driver, slapping him on the head, swearing at him and pulling his hair.