Egoism
It is possible that a passenger will not give up their seat to someone who has been assigned a priority seating position in the most severe cases. Those at risk include pregnant women and the elderly, both of whom may be particularly vulnerable to the consequences of this. When someone wants to take a seat, they may choose to stack their belongings on an open seat in order to prevent others from taking the seat from them.

Selfish individuals who use public transportation assume that they have the authority to disregard the unwritten rules of the road. This isn’t the case at all. They will not give up the additional seat, even when gently requested to do so, for the simple reason that they believe it is appropriate to take up more space than is necessary.