I can offer some explanation. i was just researching this last night to address a copyright infringement, so it's fresh in my mind..
Without going into too much detail, any photos taken are owned by the person who takes them (the photographer) unless they are employed by someone else (an employer) to take the photos, which is where it starts getting complicated, but the copyright then tends to belong to the employer. But in general, and definately in this case, copyright is owned by the person pressing the shutter button (the photographer).
As for the rider's permission, you need a model release if the photos are being used for commercial use (i.e. endorsing a product, using the person's image to sell something else). Loading photos onto a website to display, or even to sell the photos themselves, is classified as non-commercial use, and a model release isn't used.
From this site:
http://www.artslaw.com.au/LegalInformation/StreetPhotographersRights.asp
Photographing people
There are no publicity or personality rights in Australia, and there is no right to privacy that protects a person’s image.
Photographing people for a commercial purpose
If you are using your shots for a commercial purpose, such as for an advertising campaign, you should obtain a model release form signed by the subjects you are photographing to ensure you have authorisation to use their image to sell a product.
Copyright details are outlined here:
http://www.artslaw.com.au/LegalInformation/04FAQ.asp
and if you want to read about "unauthorised use of your image" :
http://www.artslaw.com.au/LegalInformation/UnauthorisedUseImage.asp
As for giving the photos out, camera gear can get VERY expensive, and a lot of time is spent in learning techniques, maintaining equipment, and running websites. Some photographers give their work away for free, but for most, it's a form of work, and asking for free photos from a photographer is like asking a cafe owner to give you free meals and coffee, or asking a musician to perform for free, or give away their music for free.
I don't mean to sound rude about it, just telling it like it is.
Hux, feel free to add/correct anything if you feel the need