Cases with evidence or practical guidance from North American institutions, paired with context about where it applies.
Read the scope: a case appears here because at least one approved source or implementation example concerns this geography. That never makes a local rule universal.
A backpack is useful and sometimes difficult to put down. In a packed carriage, it also occupies shared space and can knock into people. What does considerate travel require?
Canada and Australia, with cautious application to comparable transit systems · Only when vehicles are crowded and moving the bag is safe; mobility, medical, caregiving and safety needs take priority.
A short clip or speakerphone call may feel harmless to the person holding the phone. To everyone nearby, it becomes an unchosen soundtrack. Should headphones be the normal expectation?
Australian and United States transport examples · A cautious norm for enclosed shared spaces; accessibility, urgent communication, safety and the venue’s purpose remain exceptions.