A social media user waiting to board a Southwest flight recently cried foul over an apparent “pre-boarding scam” involving wheelchairs — while the airliner stresses that its policy complies with the law. Passengers are known to get antsy boarding and exiting planes, but Paul, whose Twitter handle is @trendready, complained about how some fellow flyers are possibly attempting to game the system by requesting wheelchair assistance and be the first ones on a flight before takeoff. “Pre-boarding scam at @SouthwestAir,” he claimed in a Saturday tweet with a photo of a line of people lined up in wheelchairs. “20 passengers...