They have posters of things that won’t fly at the check in and various points to the gate. Lithium batteries have burst into flame, as posters have said.
It sounds like the gentleman could have anticipated this and made other arrangements.
“Lithium-ion batteries are a potential fire hazard, but global standards issued by the International Air Transport Association (IATA) allow people with disabilities to travel with compact lithium batteries for medical devices in carry-on luggage.
Hodge said no one from CATSA or United Airlines would listen to him or read IATA documents he had printed out, showing his batteries are permitted on board if an airline gives prior approval. Hodge had received that permission.”