It is common to see instances of poor social etiquette on public transport, such as ungracious commuters hogging seats by placing their bags on the seats next to them, or inconsiderate commuters who swing their backpacks on trains (Some quick fixes that can win commuter support, by Mr Lim Teck Koon; Aug 4).
Bus and train operators try not to come across as high-handed and will intervene only in serious cases.
Having staff to monitor commuters' behaviour is not cost-effective and is a waste of resources because there will always be commuters who behave badly.
The operators have etiquette advisories on their website, but they cannot stop people from doing things the way they like as it is their choice.
There is no such thing as privacy on public transport, unless one takes a taxi or private-hire car.
Those of us who take trains and buses will just have to put up with such inconsiderate behaviour - there is no point getting too worked up about it.