Yeah as the comment below notes, I should have been clearer. They manually check, however I can't see it as too much of a stretch that an operator might check the feeds every now and then for such a thing. I know in the Northbridge Tunnel (Perth) they don't send fines for speeding infringements, yet if you are seen driving dangerously through the tunnel they'll get you for everything they can positively identify as illegal if they want to follow you up - i.e. in the event of an accident etc.

Source: My brother is an officer and have discussed with him about what they do and don't monitor.

Edit: old article link as the other commenter seems to have removed theirs http://www.adelaidenow.com.au/news/south-australia/sa-police...