Every airline executive in the world must have winced this week at a video going viral of a passenger forcibly removed from a double-booked seat.
Who knows how often this has happened? Until the advent of cellphone cameras an incident such as this would have been no more than a tale told by the passengers who witnessed it.
But now, any action of an over-zealous employee is capable of hurting a company as badly as United Airlines, whose shares plummeted with its public image this week.
Social media is a mixed blessing but its ability to expose bad behaviour instantly and globally, is unquestionably a force for good.
Every airline will have been checking its own procedures in the wake of United's embarrassment this week and ensuring front line staff know the limits.
Many an industry that sometimes has to deal with disappointed customers will be checking its procedures But the incident raises a wider question for airlines about this whole business of overbooking flights.
It is outrageous on the face of it. When you book something and pay for it in any other business, the provider is obliged to honour the implicit contract.
Not so airlines. Overbooking is standard practice and the industry claims it is justified.
Since not all passengers turn up for a fully-booked flight, airlines argue, they would be losing money if they had not sold some of the seats twice.
This is because the missing passengers are likely to have tickets that enable them to travel at little or no extra cost on a later flight. The airline is effectively providing two seats for the price of one in an industry where margins are tight.
It is, of course, an airline's choice to sell "flexible" fares.
It could sell all seats on every flight with no refund or transfer rights and lose no money if a passenger missed the plane.
But that would be a severe reduction of service unwelcome to many travellers, especially those flying to meetings and appointments that may go on longer than expected.
Most frequent flyers know what it feels like to miss a flight and be grateful the airline is able to provide a seat on the next one.
Getting "bumped" from an overbooked flight is the other side of that coin. It can be done inducements.
It should never be done forcefully, a seated passenger should have a right to refuse.