For a meek, passive type of child, maybe.
If she had spanked her child in front of everyone simply for saying, "Bye, bye, plane," she might've been arrested for child abuse.
Nah, in this case, the flight attendant abused her power.
“For a few moments, perhaps. Done properly it is all over-and-done-with in about five minutes”
Louder screaming and possible arrest on returning to the terminal (or at least a report to DSS)