US and Australian Law differs. While I don't claim to be an expert on either there is in Australia basically no restriction upon taking still photographs in or of public places (including places to which the public has access on legitimate business such as railways stations), and no consent is required of anyone whose image might be captured as a part of the overall scene. They might object but there is no right
of objection. and unless some other law is allegedly broken no other legal redress.
As I understand Australian Law consent is
required if a person is to be the main or sole subject
of the photograph and is clearly identifiable and
is wearing an identifiable uniform (or other similarly recogniseable clothing) such as a Police officer or member of railway staff.
If these people happen to be included as incidental to the main image subject then there is no legal restraint on image capture as such.
laws restricting the capture of certain images which might include Prohibited Places (jails, military locations etc) or scenes of crime, distress or security interest which might include road or rail accidents, suspect packages and the like.
It may also be unlawful to use images captured lawfully for purposes which are themselves unlawful such as the publication (including on the internet) of images of minors, of indecently attired persons or of lewd acts.
Basic common sense applies. It's fine to take pics of your young kiddies playing on the beach and to have other (unknown) people included as incidental to those images. But take pics of someone else's kids without their knowledge and consent and you might be considered to be behaving inappropriately.
Consent is also required in most cases where an image is submitted for intended publication and is taken on, of or from a place other than public land. This applies whether or not any financial gain is sought or offered.
The capture of moving images can require consent in similar circumstances but again there are generally no restrictions in public places so long as no other law (such as obstruction) is contravened.
Images taken by accredited press and media photographers fall within certain legal dispensations. Thus it can be in order for a journalist to take pictures of a fatal accident but not a private individual. The former is considered to be acting in a professional capacity and in the public interest; the latter may be thought of as an uninvited rubber-neck.
If you happen to be in such a situation and manage to grab some photos then exercise discretion before posting them to YouTube or the many "Were You There?" news boards.