Is kissing on public transport rude?
Lovers should be considerate to others when kissing on public transport, authorities in Vienna say. Are ostentatious displays of affection really so rude, asks Olivia Sorrel-Dejerine.
Eating smelly food, talking too loudly and putting your feet on the seats all are widely agreed to be unacceptable on buses and trains.
Being overly amorous can be just as inconsiderate, according to the company Wiener Linien, which operates public transport in the Austrian capital Vienna.
A public information film produced by the firm shows examples of passengers behaving less than thoughtfully - someone picking their nose, an unattended dog drooling and a couple, in the words of Wiener Linien spokeswoman Anna Maria Reich, "kissing untamed".
Reich told the BBC that, contrary to some reports, kissing was neither banned on the network nor subject to fines. But she added that the campaign was about asking customers to "behave considerately".
It's a move that will bring cheer to some, but dismay others.
Railway stations have long been depicted as romantic places in movies such as 1945's Brief Encounter, where a woman falls in love with a stranger she meets on a train platform.
Sometimes, however, it is not as poetic when you are actually witnessing a couple wildly embracing in front of you in real life.
"A kiss on the cheek is fine in public but a kiss on the lips, especially with the tongue, is not a correct behaviour because it is such an intimate act," says William Hanson, an etiquette and protocol consultant.
"Kissing in public almost devalues this sign of affection because it is supposed to be intimate," he says.
Yet being able to publicly display your affection can be an act of liberation for some people.
In May 2013, around 100 people kissed at a subway station in Turkey's capital, Ankara, to protest against the subway authorities' admonishment of a couple who locked lips in public.
Kissing used to be seen as a very western thing. But it seems the younger generation is becoming more liberal with the rise of public displays of affection in other countries including some parts of India, where such behaviour was once unthinkable.
Nevertheless, however empowering some find it, there are some freedoms which need to be exercised considerately, says Hanson, "kissing being one of them".
Impatient couples may just have to get a room.