Mike McGlamry was strolling through Atlanta's Piedmont Park when three people on electric scooters zipped by him—and he morphed into what he called “a grumpy old man.”

The riders weren't wearing helmets. McGlamry, who represented pro football players in a class action over concussions, pulled out his phone, shot photos of the riders, called his secretary and dictated an open letter that is now on his LinkedIn page.

McGlamry called scooter policies encouraging riders to wear helmets “a farce.” He said the scooter companies and city officials were on notice that riders never wear them. “You all are being an accessory before the fact for facilitating, encouraging and/or ignoring violations of laws and safety,” McGlamry concluded.

Beyond McGlamry's social media outburst, real cases about the scooters that have descended on urban areas around the country are brewing, along with a host of thorny questions for courts and lawmakers.

Among them is whether scooter companies can shield themselves from liability in accidents by requiring riders to sign waivers. Timothy Lytton, an associate dean at Georgia State University College of Law, said courts will have to balance the assumption of risk accepted by riders against public policy frowning on people giving up rights to use vital public services. Waivers aren't required to board a city bus, for example, so if scooters are truly transforming commuting, perhaps public policy won't allow waivers for scooters, either.

Lytton, who works with the law school's Center for Law, Health and Society and has written about litigation against the gun industry, said many scooter cases will be brought, and “They will be all over the map.”

In Florida, Ashanti Jordan is a security guard who has been in a persistent vegetative state since she and the Lime scooter she was riding collided with a car in December, according to a lawsuit against Lime. Todd Falzone, a Fort Lauderdale attorney representing the woman's mother, said their case will get around the liability waiver the woman signed because he claims Lime's policy violated city law. The company told riders to use the scooter in the street, even though city law allowed scooters only on sidewalks, he said, creating “negligence per se.”

A representative from Lime could not be reached. Its website states: “Safety is our top priority. Lime has developed a series of educational videos, dedicated instructional pages and in-app messages to ensure riders know and abide by applicable rules and regulations. We also offer free helmets to all riders with over $10 in Lime credit in their account.”

Falzone said waivers and helmet use will be “a huge issue” as accidents and scooter litigation spread.

He said scooter companies could effectively require riders to use helmets “if they really wanted to.” The companies, which already require riders to take photos of their driver's licenses and credit cards, could require riders to take a photo of themselves wearing a helmet. Or the scooter could be designed not to work unless a helmet that was attached to the scooter is removed from a holder, presumably to be put on the rider's head.

Falzone suggested companies don't want to take such measures because ridership would “drop dramatically.”

A study of 249 emergency room patients who were in electric scooter accidents found that only 4 percent of riders used helmets, according to JAMA Network Open, a site of the American Medical Association.

Kaiser Health News reported this month that, “In Atlanta, the number of injuries per month has increased from about 30 to about 100, said Dr. Hany Atallah, chief of emergency medicine at Grady Health System.”

GSU's Lytton said another aspect of scooter litigation will be whether scooter companies owe any duty to do more than provide a product without defects. “It's an open question,” he said, whether scooter companies should worry about whether their product is used safely.

Courts will have to weigh whether a ruling against scooter companies for not providing more safety measures for riders would essentially put an end to the industry. “Courts are uncomfortable,” said Lytton, with decisions “that serve as a kind of a ban” because such matters are usually left to legislatures.

McGlamry, the plaintiffs lawyer who dictated a letter in the park after seeing helmetless riders, said he was particularly upset to hear some states' helmet laws are being lifted. In California, Gov. Jerry Brown last year signed legislation that said adults were not required to wear helmets on electric scooters.

“Somebody's going to get really hurt,” McGlamry said. “Who's paying for all this?”